阅读说明：本技术 传感器、形成传感器的方法和装置 (Sensor, method and apparatus for forming sensor ) 是由 詹姆斯·拉塞尔·韦伯斯特 彼得·J·席勒 理查德·艾伦·范杜森 伊恩·罗伯特·哈蒙 于 2014-05-23 设计创作，主要内容包括：公开的传感器可以包括至少一个谐振器(在一些实施例中,至少两个谐振器)和可以与谐振器联合形成的各种其它结构。在实施例中至少一个谐振器可以包括底电极、压电层、和顶电极,其中压电层被定位在底电极和顶电极之间。(The disclosed sensors may include at least one resonator (in some embodiments, at least two resonators) and various other structures that may be formed in conjunction with the resonator. In an embodiment at least one resonator may comprise a bottom electrode, a piezoelectric layer, and a top electrode, wherein the piezoelectric layer is positioned between the bottom electrode and the top electrode.)

1. A sensor, comprising:

at least a first resonator having a first surface and an opposing second surface, and comprising:

a bottom electrode;

a piezoelectric layer; and

a top electrode is arranged on the top of the substrate,

wherein the piezoelectric layer is positioned between the bottom electrode and the top electrode;

a metal oxide layer positioned on at least the second surface of the first resonator, the metal oxide layer having a thickness from aboutTo about

a coupling layer comprising silicon atoms, the silicon atoms of the coupling layer being bonded to oxygen atoms in the metal oxide layer; and

a molecule recognition component layer that contains a molecule recognition component and the molecule recognition component is bonded to the silane layer.

2. A sensor, comprising:

at least first and second resonators, each of said first and second resonators having a first surface and an opposing second surface, and each of said resonators comprising:

a bottom electrode;

a piezoelectric layer; and

a top electrode is arranged on the top of the substrate,

wherein the piezoelectric layer is positioned between the bottom electrode and the top electrode;

a Bragg mirror stack beneath the first surfaces of the first and second resonators; and

a molecular recognition component layer positioned adjacent to the second surfaces of both the first and second resonators;

wherein the at least first and second resonators are connected in series.

3. A sensor, comprising:

at least a first resonator having a first surface and an opposing second surface, and comprising:

a bottom electrode;

a piezoelectric layer; and

a top electrode is arranged on the top of the substrate,

wherein the piezoelectric layer is positioned between the bottom electrode and the top electrode;

a coupling layer positioned adjacent to the second surface of the at least first resonator; and

a molecule recognition component layer having a substantially circular shape and containing a molecule recognition component bonded to the coupling layer.

4. A sensor, comprising:

at least first and second resonators, each of the first and second resonators having substantially the same shape, each of the at least first and second resonators having a first surface and an opposing second surface, and each of the resonators comprising:

a bottom electrode;

a piezoelectric layer; and

a top electrode is arranged on the top of the substrate,

wherein the piezoelectric layer is positioned between the bottom electrode and the top electrode;

a metal oxide layer positioned on at least the second surface of both the first and second resonators, the metal oxide layer having a thickness from about

a coupling layer comprising silicon atoms, the silicon atoms of the silane layer being bonded to oxygen atoms in the metal oxide layer; and

a molecule recognition component layer containing a molecule recognition component bonded to the silane layer,

wherein the at least first and second resonators are connected in series.

5. A sensor according to any one of claims 1 or 3, further comprising at least a second resonator.

6. A sensor according to any one of claims 2, 4 or 5, wherein the at least first and second resonators are electrically connected in series.

7. A sensor according to any one of claims 2, 4 or 5, wherein the at least first and second resonators have substantially different shapes.

8. A sensor according to any one of claims 2, 4 or 5, wherein the at least first and second resonators have substantially the same shape.

9. The sensor of claim 8, wherein the at least first and second resonators have a substantially semi-circular shape.

10. The sensor of claim 8, wherein the at least first and second resonators have a substantially rectangular shape.

11. The sensor of any one of claims 2 or 3, further comprising a metal oxide layer positioned on at least the second surface of the at least first resonator.

12. The sensor of any one of claims 1, or 4-11, wherein the metal oxide layer is formed from TiO₂、SiO₂、A1₂O₃Or ZnO.

13. The sensor of any of claims 1, or 4-12, wherein the metal oxide layer is TiO₂。

14. The sensor of any of claims 1, or 4-13, wherein the metal oxide layer has a thickness of from about

15. The sensor of any of claims 1, or 4-14, wherein the metal oxide layer has a thickness of from about

16. The sensor of any of claims 1, or 4-15, wherein the metal oxide layer has a thickness of from about

17. The sensor of any of claims 1, or 4-16, wherein the metal oxide layer is deposited using atomic layer deposition.

18. The sensor of any of claims 1, or 4-17, wherein the metal oxide layer is deposited over the entirety of the sensor.

19. The sensor of claim 2, further comprising a coupling layer.

20. The sensor of any one of claims 3 or 19, further comprising an oxide layer positioned on at least the second surface of the at least first resonator.

21. The sensor of claim 20, wherein the coupling layer comprises silicon atoms and the silicon atoms of the coupling layer are bonded to oxygen atoms in the metal oxide layer.

22. The sensor of any one of claims 1, 3-21, wherein the coupling layer comprises an epoxy silane.

23. The sensor of any one of claims 1-22, wherein the molecular recognition element is an antibody.

24. The sensor of any one of claims 1-23, wherein the molecular recognition component layer has a substantially circular shape.

25. The sensor of any one of claims 1-24, wherein the sensor has a substantially circular shape.

26. The sensor of any one of claims 1, or 3-25, wherein the sensor further comprises a bragg mirror stack positioned below the bottom electrode of the at least first resonator.

27. An assembly, comprising:

at least one active sensor and at least one reference sensor, wherein each of the active sensor and the reference sensor comprises:

at least a first resonator having a first surface and an opposing second surface, and comprising:

a bottom electrode;

a piezoelectric layer; and

a top electrode is arranged on the top of the substrate,

wherein the piezoelectric layer is positioned between the bottom electrode and the top electrode;

a metal oxide layer positioned at both the at least one active sensor and the at least one reference sensorThe metal oxide layer has a thickness of from about

a coupling layer comprising silicon atoms, the silicon atoms of the silane layer being bonded to oxygen atoms in the metal oxide layer;

a molecule recognition component layer, the molecule recognition components of the molecule recognition component layer being bound to the coupling layer throughout the at least one active sensor; and

a layer of reference binding material, the reference binding material of the layer of reference binding material being bound to the coupling layer throughout the at least one reference sensor,

wherein the reference binding material is different from the molecular recognition component.

28. An assembly, comprising:

at least one active sensor and at least one reference sensor, wherein each of the active sensor and the reference sensor comprises:

at least first and second resonators, each of said first and second resonators having a first surface and an opposing second surface, and each of said resonators comprising:

a bottom electrode;

a piezoelectric layer; and

a top electrode is arranged on the top of the substrate,

wherein the piezoelectric layer is positioned between the bottom electrode and the top electrode of each of the first and second resonators, and wherein the at least first and at least second resonators of each of the active sensor and the reference sensor are independently connected in series; and

a Bragg mirror stack below the first surfaces of the first and second resonators of the at least one active sensor and the reference sensor;

a molecular recognition component layer positioned adjacent to the second surfaces of the first and second resonators of the active sensor; and

a layer of reference bonding material positioned adjacent to the second surfaces of both the first and second resonators of the reference sensor,

wherein the reference binding material is different from the molecular recognition component.

29. An assembly, comprising:

at least one active sensor and at least one reference sensor, wherein each of the active sensor and the reference sensor comprises at least a first resonator having a first surface and an opposing second surface, the at least one resonator comprising:

a bottom electrode;

a piezoelectric layer; and

a top electrode is arranged on the top of the substrate,

wherein the piezoelectric layer is positioned between the bottom electrode and the top electrode;

a coupling layer positioned adjacent to the second surface of at least the first resonator of the active sensor and the reference sensor, the coupling layer comprising silicon atoms;

a molecule recognition component layer, the molecule recognition components of which are bonded to the coupling layer throughout the at least one active sensor, the molecule recognition component layer having a substantially circular shape; and

a layer of reference bonding material, the reference bonding material of the layer of reference bonding material being bonded to the coupling layer throughout at least one reference sensor, the layer of reference bonding material having a substantially circular shape,

wherein the reference binding material is different from the molecular recognition component.

30. An assembly, comprising:

at least one active sensor and at least one reference sensor, wherein each of the at least one active sensor and the at least one reference sensor comprises:

first and second resonators, each of the first and second resonators having substantially the same shape and each of the first and second resonators having a first surface and an opposing second surface, and each of the resonators comprising:

a bottom electrode;

a piezoelectric layer; and

a top electrode is arranged on the top of the substrate,

wherein the piezoelectric layer is positioned between the bottom electrode and the top electrode, and

the first and second resonators of each of the active sensor and the reference sensor are independently connected in series;

a metal oxide layer positioned on at least the second surfaces of the first and second resonators of the active and reference sensors, the metal oxide layer having a thickness from about

a coupling layer comprising silicon atoms, the silicon atoms of the coupling layer being bonded to oxygen atoms in the metal oxide layer;

a molecule recognition component layer, the molecule recognition components of the molecule recognition component layer being bound to the coupling layer throughout the at least one active sensor; and

a layer of reference binding material, the reference binding material of the layer of reference binding material being bound to the coupling layer throughout the at least one reference sensor,

wherein the reference binding material is different from the molecular recognition component.

31. The assembly according to any of claims 27-30, wherein the assembly comprises at least one reference sensor and at least two active sensors.

32. The assembly according to any of claims 27-31, wherein the assembly comprises at least one reference sensor and at least three active sensors.

33. The assembly according to any of claims 27-32, wherein both the at least one active sensor and the at least one reference sensor have substantially the same shape.

34. The assembly according to any of claims 27-33, wherein both the at least one active sensor and the at least one reference sensor have a substantially circular shape.

35. A sensor according to any of claims 1 to 26 arranged in an assembly comprising at least one other sensor.

36. A method of forming a sensor, comprising:

forming at least a first resonator having a first surface and an opposing second surface, the first resonator comprising a bottom electrode; a piezoelectric layer on at least a portion of the bottom electrode; and a top electrode on at least a portion of the piezoelectric layer; and

depositing a metal oxide layer on the second surface of the at least first resonator, the metal oxide being deposited using Atomic Layer Deposition (ALD).

37. The method of claim 36, further comprising forming a silane comprising a coupling layer on the metal oxide layer; and

the molecular recognition element composition is deposited on the silane comprising the coupling layer.

38. The method of claim 37, wherein the molecular recognition component composition is deposited so as to form a molecular recognition component layer having a substantially circular shape covering the at least first resonator.

39. A method of forming a sensor, comprising:

forming at least a first resonator having a first surface and an opposing second surface, the first resonator comprising a bottom electrode; a piezoelectric layer on at least a portion of the bottom electrode; and a top electrode on at least a portion of the piezoelectric layer; and

forming a coupling layer on the second surface of the at least first resonator; and

depositing a molecular recognition component composition on the coupling layer, the molecular recognition component composition being deposited so as to form a molecular recognition component layer having a substantially circular shape covering the at least first resonator.

40. The method of claim 36 or 39, further comprising electrically connecting the first and second resonators in series.

41. The method of any of claims 36-40, further comprising dicing a wafer on which the sensors are formed.

42. The method of any one of claims 36-41, further comprising mounting the sensor on an electrical connection board.

43. The method of claim 41 or 42, wherein the cutting occurs before forming the coupling layer.

Background

There are many instruments and measurement techniques used for diagnostic testing of materials related to medicine, veterinary medicine, environmental, biohazards, bioterrorism, agricultural commodities, and food safety. Diagnostic tests traditionally require long reaction times to obtain meaningful data, involve expensive remote or cumbersome laboratory equipment, require large sample volumes, utilize multiple reagents, require trained users, and can involve significant direct and indirect costs. For example, in the human and veterinary diagnostic markets, most tests require that a sample be collected from a patient and later sent to a laboratory where results are not available for hours or days. As a result, the caregiver must wait to treat the patient.

The point of use of protocols for diagnostic testing and analysis (or points of interest when discussing humans or veterinarians), while addressing most of the noted disadvantages, is still somewhat limited. Even the point of use of some of the available protocols is limited in sensitivity and reproducibility compared to laboratory tests. There is also often a significant direct cost to the user, as there may be separate systems for each point of use available.

Disclosure of Invention

Disclosed herein is a sensor comprising at least a first resonator having a first surface and an opposing second surface, and the first resonator further having a bottom electrode; a piezoelectric layer; and a top electrode, wherein the piezoelectric layer is positioned between the bottom electrode and the top electrode; a metal oxide layer positioned on at least the second surface of the first resonator, the metal oxide layer having a thickness of from about

To about

And the metal oxide layer comprises oxygen atoms; a silane layer including silicon atoms, the silicon atoms of the silane layer being bonded to oxygen atoms in the metal oxide layer; and a molecule recognition component layer that includes the molecule recognition component and is bonded to the silane layer.

Also disclosed herein is a sensor comprising at least first and second resonators, each of the first and second resonators having a first surface and an opposing second surface and each resonator having a bottom electrode; a piezoelectric layer; and a top electrode, wherein the piezoelectric layer is positioned between the bottom electrode and the top electrode; a bragg mirror stack beneath the first surfaces of both the first and second resonators; and a molecule recognition component layer positioned adjacent to the second surfaces of both the first and second resonators, wherein at least the first and second resonators are connected in series.

Also disclosed herein is a sensor comprising at least first and second resonators, each of the at least first and second resonators having a first surface and an opposing second surface, and each resonator having a bottom electrode; a piezoelectric layer; and a top electrode, wherein the piezoelectric layer is positioned between the bottom electrode and the top electrode; a coupling layer; and a molecule recognition component layer having a substantially circular shape and including a molecule recognition component bonded to the coupling layer.

Also disclosed herein is a sensor comprising at least first and second resonators, each of the at least first and second resonators having substantially the same shape, and each of the first and second resonators having a first surface and an opposing second surface, and each resonator comprising: a bottom electrode; a piezoelectric layer; and a top electrode, wherein the piezoelectric layer is positioned between the bottom electrode and the top electrode; a metal oxide layer positioned on at least the second surfaces of both the first and second resonators, the metal oxide layer having a thickness of from about

To about

And the metal oxide layer comprises oxygen atoms; a silane layer including silicon atoms, the silicon atoms of the silane layer being bonded to oxygen atoms in the metal oxide layer; and a molecule recognition component layer including a molecule recognition component bonded to the silane layer, wherein at least the first and second resonators are connected in series.

Also disclosed herein is an assembly comprising at least one active sensor and at least one reference sensor. The at least one active sensor and the at least one reference sensor may generally include a bottom electrode, a piezoelectric layer, and a top electrode. The assembly may further include additional structures or components discussed herein. At least one reference sensor in the disclosed assembly includes a layer of reference binding material throughout the at least one reference sensor and at least one active sensor includes a layer of molecular recognition binding material throughout the at least one active sensor.

Also disclosed herein is a method of forming a sensor, comprising forming at least first and second resonators, each having a first surface and an opposing second surface, each of the first and second resonators having a bottom electrode; a piezoelectric layer on at least a portion of the bottom electrode; and a top electrode on at least a portion of the piezoelectric layer; and depositing a metal oxide layer on the second surfaces of both the first and second resonators, the metal oxide being deposited using Atomic Layer Deposition (ALD).

Also disclosed herein is a method of forming a sensor, comprising forming at least first and second resonators, each having a first surface and an opposing second surface, each of the first and second resonators having a bottom electrode; a piezoelectric layer on at least a portion of the bottom electrode; and a top electrode on at least a portion of the piezoelectric layer; and forming a coupling layer on the second surfaces of at least the first and second resonators; and depositing the molecular recognition component composition on the coupling layer, the molecular recognition component covering at least both the first and second resonators being deposited in a substantially circular shape.

These and various other features will be apparent from a reading of the following detailed description and a review of the associated drawings.

Drawings

Fig. 1A and 1B are schematic depictions of a cross-sectional view (fig. 1A) and a top view (fig. 1B) of an illustrative disclosed sensor.

Fig. 2A and 2B are schematic depictions of a cross-sectional view (fig. 2A) and a top view (fig. 2B) of an illustrative disclosed assembly including the disclosed sensor.

FIG. 3 depicts a cross-sectional view of an illustrative disclosed sensor.

Fig. 4 depicts a cross-sectional view of an illustrative disclosed sensor.

Fig. 5A and 5B depict a cross-sectional view (fig. 5A) and a top view (fig. 5B) of an illustrative disclosed sensor.

Fig. 6A to 6D are Smith plan views (Smith plots) of various resonators.

The schematic drawings are not necessarily to scale. Like reference numerals are used in the figures to refer to like parts, steps and the like. It should be understood, however, that reference to a component in a given figure by a reference number is not intended to limit the component in another figure labeled with the same reference number. Further, the use of different reference numbers to refer to components is not intended to indicate that the different numbered components cannot be the same or similar.

Detailed Description

The disclosed sensors may include at least one resonator (in some embodiments, at least two resonators) and various other structures that may be associated with the resonator. At least one resonator in an embodiment may include a bottom electrode, a piezoelectric layer, and a top electrode.

In some embodiments, the disclosed sensor may include at least first and second resonators, an oxygen containing layer on one surface of the resonators, a coupling layer on the oxygen containing layer, and a molecular recognition layer on the coupling layer. FIG. 3 depicts sensor 300In the illustrative embodiment, the sensor 300 includes a first resonator 302, an oxygen containing layer 340, a coupling layer 330, and a molecular recognition layer 320. In some embodiments, the oxygen containing layer may have only one layer

And in some embodiments, no greater than

In some embodiments, the sensor may include at least a first resonator having a first surface and an opposing second surface, and the first resonator includes a bottom electrode; a piezoelectric layer; and a top electrode, wherein the piezoelectric layer is positioned between the bottom electrode and the top electrode; a metal oxide layer is positioned on the second surface of the at least first resonator, the metal oxide layer having a thickness of from about

To about

And the metal oxide layer comprises oxygen atoms; a silane layer including silicon atoms, the silicon atoms of the silane layer being bonded to oxygen atoms in the metal oxide layer; and a molecule recognition component layer that includes a molecule recognition component and the molecule recognition component is bonded to the silane layer. In some embodiments, such a sensor may also include at least a second resonator, the second resonator including a bottom electrode; a piezoelectric layer; and a top electrode, wherein the piezoelectric layer is positioned between the bottom electrode and the top electrode.

Methods of forming such sensors are also disclosed herein. An illustrative method of forming a sensor may include forming at least first and second resonators each having a first surface and an opposing second surface, each of the first and second resonators including a bottom electrode; a piezoelectric layer on at least a portion of the bottom electrode; and a top electrode on at least a portion of the piezoelectric layer; and depositing a metal oxide layer on the second surfaces of both the first and second resonators, the metal oxide layer being deposited using Atomic Layer Deposition (ALD). In some embodiments, the oxygen containing layer may be formed using, for example, Atomic Layer Deposition (ALD).

Disclosed herein is a resonant sensor that can function as a Thin Film Bulk Acoustic Resonator (TFBAR) sensor. The TFBAR sensor includes a layer of piezoelectric material bounded on opposite sides of an electrode. When the sensor is driven by a signal in the resonance band of the resonator, both surfaces of the sensor are subjected to a vibrating motion. One surface of the resonator may be adapted to provide binding sites for an analyte of interest in a sample to be analysed. The combination of the materials of interest on the surface of the resonator changes the resonance characteristics of the sensor. Such changes can be detected and analyzed to provide quantitative information about the analyte of interest. In general, resonant sensors provide better results when the binding material of interest is physically bound to the sensor itself as closely as possible (the piezoelectric material is bound to the opposite side of the electrodes). To this end, sensors are typically fabricated by using the smallest possible materials and/or layers necessary to provide binding for the analyte of interest.

Sensor attachment materials that can bind components of the sample of interest directly to the top electrode have previously been used. Rather, some embodiments of the disclosed sensor may include at least one additional layer on top of the top electrode, before the material that may bind the components of the sample of interest. In some embodiments, one of the additional layers may include oxygen atoms that may be later bonded to the coupling layer, and a material capable of bonding the material of interest may be bonded to the coupling layer. Surprisingly, the addition of an additional layer between the top electrode and the top electrode, which moves the material of interest (e.g., the majority of the material of interest) away from the sensor, does not reduce the signal provided by the sensor and may actually provide a better signal from the sensor in some embodiments. It is believed, but not relied upon, that an oxygen containing layer disposed on the top electrode may provide rigidity to the sensor. Rendering the sensor more rigid may reduce the damping of the resonance, thereby maintaining or even increasing the signal from the sensor.

In some embodiments, the disclosed sensor may include at least first and second resonators electrically connected in series, a bragg mirror stack below the first and second resonators, and a molecular recognition component layer above the first and second resonators. Fig. 4 depicts an illustrative embodiment of a sensor 400 that includes a first resonator 402, a second resonator 412, a bragg mirror stack 415, and a molecular recognition layer 420. In some embodiments, the sensor may include at least first and second resonators, each of the first and second resonators having a first surface and an opposing second surface and each resonator having a bottom electrode; a piezoelectric layer; and a top electrode, wherein the piezoelectric layer is positioned between the bottom electrode and the top electrode; a bragg mirror stack beneath the first surfaces of both the first and second resonators; and a molecular recognition component layer positioned adjacent to the second surfaces of both the first and second resonators, wherein at least the first and second resonators are connected in series.

First and second resonators having a contiguous configuration, such as the resonator depicted in fig. 4, for example, may become coupled through the substrate on which they are formed. Such a coupling may be considered undesirable. The use of an acoustic bragg mirror stack may be used to mitigate such coupling. While it may be advantageous to reduce such coupling by a bragg mirror stack, the bragg mirror stack can create parasitic resonances. Connecting the first and second resonators in series may reduce or prevent possible parasitic resonances. The electrical and mass loading effects of connecting the first and second resonators in series may be substantially equal to (in some embodiments, greater than) the single resonator minus the parasitic resonance induced by the bragg mirror stack.

In some embodiments, the disclosed sensor may include at least a first resonator, a coupling layer on the first resonator, and a molecular recognition component layer coupled to the coupling layer. Fig. 5A and 5B depict cross-sectional and top views of an illustrative embodiment of a sensor 500, the sensor 500 including a first resonator 502, a coupling layer 530, and a substantially circular molecular recognition layer 520. The generally circular shape of the molecular recognition layer 520 can be seen in particular in fig. 5B. It should be noted that the at least first resonator in such embodiments may have any configuration, and the molecular recognition component layer 520 may overlay more than just the at least first resonator, e.g., the at least second resonator, or a combination thereof. In some embodiments, the disclosed sensor may include at least a first resonator having a first surface and an opposing second surface and the resonator having a bottom electrode; a piezoelectric layer; and a top electrode, wherein the piezoelectric layer is positioned between the bottom electrode and the top electrode; a coupling layer positioned adjacent to the second surface of the at least first resonator; and a molecule recognition component layer having a substantially circular shape and including a molecule recognition component of the binding coupling layer.

Methods of forming such sensors are also disclosed herein. An illustrative method may include forming at least a first resonator having a first surface and an opposing second surface, the first resonator having a bottom electrode; a piezoelectric layer on at least a portion of the bottom electrode; and a top electrode on at least a portion of the piezoelectric layer; and forming a coupling layer on the second surface of at least the first resonator; and depositing a molecular recognition component composition on the coupling layer, the molecular recognition component composition being deposited so as to form a molecular recognition component layer having a substantially circular shape covering at least the first resonator.

The overall generally circular shape of such a sensor may be formed at least in part by way of forming a layer of the molecular recognition component (the material that binds the analyte of interest). The generally circular shape may provide for the use of a minimal amount of the composition comprising the molecular recognition component, because as the composition comprising the molecular recognition component is deposited on the formed sensor in a drop-wise manner, the inherent surface/liquid interactions, e.g., contact angle and surface tension, will naturally provide a generally circular shape, as the solvent in the volatilization of the composition.

Any of the details disclosed herein with respect to any particular or alternative portion of the disclosed sensor may be used as applicable to any of the above types of sensors. Moreover, the assembly or other disclosed device may use any of the above disclosed types of sensors (optionally including any of the features discussed herein).

The disclosed sensors may be described by their overall shape. The disclosed sensors can have various shapes. In some embodiments, the disclosed sensors may be square, rectangular, hexagonal, circular, or virtually any other shape. In some embodiments, the disclosed sensors may have a circular shape. The disclosed single sensor may include at least two resonators. In some embodiments, at least two resonators that are part of a single sensor may have substantially the same shape. In some embodiments, at least two resonators may have different shapes.

In some embodiments, a single sensor may include at least two resonators configured in such a way that the overall shape of the region containing the at least two resonators may be used to describe the sensor and may be referred to as the configuration of the resonators. In some embodiments, the overall shape of the sensor and the configuration of the resonator may be the same, and in some embodiments, the overall shape of the sensor and the configuration of the resonator may be different. In some embodiments, at least two resonators that are part of a single sensor may have the same generally semicircular shape, providing an overall generally circular resonator configuration, e.g., two generally semicircular resonators having planes configured with semi-circles facing each other. In some embodiments, four (4) resonators may be used in the sensor, for example, each of the four resonators shaped like a quarter of a circle (1/4). The overall resonator configuration in such embodiments may be described as generally circular. In some embodiments, the at least two resonators may have at least two different shapes that form a generally circular shape when configured in the disclosed sensor. For example, one resonator may be one quarter of a circle (1/4) and the other resonator may be the other three quarters of a circle (3/4). The overall resonator configuration in such embodiments may be described as generally circular. In some embodiments, four (4) resonators, e.g., having a substantially square (or rectangular) shape, may be formed and configured into a larger substantially square (or rectangular) shape. The overall resonator configuration in such embodiments may be described as square or rectangular. Embodiments having a square (or rectangular) resonator configuration, for example, may have a substantially circular sensor shape. In embodiments where the sensor shape and resonator configuration are different, the sensor shape may be dictated or controlled by the shape of the molecular recognition component layer (described below) formed thereon.

The overall generally circular shape of some disclosed sensors may be formed at least in part by way of forming a layer of the molecular recognition component (the material that binds the analyte of interest). The generally circular shape of the molecule recognition component layer may provide for the use of a minimal amount of the composition comprising the molecule recognition component, as the inherent surface/liquid interactions, e.g., contact angle and surface tension, naturally provide a generally circular shape as the composition comprising the molecule recognition component is deposited in a drop-wise fashion on the formed sensor.

In some embodiments, the combination of a sensor having a generally circular sensor shape with an oxide layer and a molecular recognition component layer formed thereon may provide a TFBAR sensor that may be useful in a larger system for detecting and quantifying an analyte of interest in a sample.

Fig. 1A and 1B depict illustrative disclosed sensors. The disclosed sensor may generally include at least first and second resonators. Some disclosed sensors may also include an oxygen containing layer, a coupling layer, and a molecular recognition component layer. Fig. 1A shows an illustrative sensor 100. The illustrative sensor 100 includes a first resonator 102 and a second resonator 112. In some embodiments, first resonator 102 and second resonator 112 may be substantially identical, and in some embodiments, they may be different in one or more respects. Each of the first resonator 102 and the second resonator 112 has a first surface 105 and 115, respectively, and an opposing second surface 107 and 117, respectively. The first resonator 102 and the second resonator 112 may be positioned at a distance. This distance is depicted as d in fig. 1B. In some embodiments, first resonator 102 and second resonator 112 may be spaced apart (d) by at least 1 micrometer (μm), and in some embodiments, they may be spaced apart (d) by at least 45 μm. In some embodiments, first resonator 102 and second resonator 112 may be separated by no more than 100 μm (d), and in some embodiments, they may be separated by no more than 75 μm (d). In some embodiments, the spacing between the two resonators need not be constant; the spacing between two resonators need not be the same as the spacing between two other resonators, or any combination thereof.

Each resonator, e.g., at least the first resonator 102 and the second resonator 112, may include bottom electrodes 104 and 114, piezoelectric layers 106 and 116, and top electrodes 108 and 118. Piezoelectric layers 106 and 116 are positioned between bottom electrodes 104 and 114 and top electrodes 108 and 118. Additional layers not depicted in FIG. 1A may also be interspersed between, above, below, or combinations thereof with the indicated layers.

It should be noted that the bottom electrodes 104 and 114 of the first resonators 102 and 112 may be part of a single layer. As are piezoelectric layers 106 and 116 and top electrodes 108 and 118. This means that the bottom electrodes (or one or both of the bottom electrode, top electrode, and piezoelectric layer) of at least two resonators may have a shared bottom electrode (or other combination) or the bottom electrodes (or other combination) may be different but formed from a single layer of material. In embodiments where the first resonator 102 and the second resonator 112 comprise at least two structures (bottom electrode, piezoelectric layer, or top electrode) formed from a single layer of material, the layers of material forming the different structures need not be present across the entire larger device housing the sensor (if such a larger structure is present). For example, the sensor may include bottom electrodes 104 and 114 formed from a single layer of material; and piezoelectric layers 106 and 116 formed from a single layer of material. The layers forming the bottom electrode and piezoelectric layer, respectively, need not be identical. For example, portions of the piezoelectric material may be removed at various locations across the sensor. It should also be noted that the disclosed resonators, e.g., the first and second resonators 102 and 112, are formed only where the bottom and top electrode materials overlap with the piezoelectric material therebetween. In some embodiments, the bottom electrodes 104 and 114, the piezoelectric layers 106 and 116, and the top electrodes 108 and 118 may all be formed from separate deposited layers of bottom electrode material, piezoelectric material, and top electrode material, respectively. It should also be noted that in some embodiments, the multiple bottom electrodes, top electrodes, piezoelectric layers, or any combination thereof of the multiple resonators may be formed integrally and independently as separate resonators, but may be formed from a single layer of material. It should also be noted that the shape of any one of the bottom electrode, the piezoelectric layer, and the top electrode or each of the bottom electrode, the piezoelectric layer, and the top electrode may be different from the shape of any one of the others.

The first and second resonators 102 and 112 may be made of different materials. In some embodiments, the bottom electrodes 104 and 114 may be made of the same material. Illustrative materials for the bottom electrodes 104 and 114 may include, for example, aluminum (Al), gold (Au), tungsten (W), copper (Cu), molybdenum (Mo), and tantalum (Ta). In some embodiments, the bottom electrodes 104 and 114 may both comprise aluminum. In some embodiments, the top electrodes 108 and 118 may be made of the same material. Illustrative materials for top electrodes 108 and 118 can include, for example, Au, Al, W, Cu, Mo, and Ta. In some embodiments, the top electrodes 108 and 118 may both comprise gold. In some embodiments, piezoelectric layers 106 and 116 can be made of the same material. Illustrative materials for piezoelectric layers 106 and 116 can include, for example, aluminum nitride (AlN), zinc oxide (Zn), and lead zirconate titanate (PZT). In some embodiments, piezoelectric layers 106 and 116 can both comprise aluminum nitride.

In some embodiments, at least the first and second resonators 102 and 112 may be described as having substantially the same shape. In some embodiments, the first and second resonators may each be described as having a semi-circular shape. Fig. 1B depicts a top view of an illustrative sensor that includes first resonator 102 and second resonator 112 that both have a substantially semi-circular shape. Sensor 100 may be described as having a generally circular resonator configuration with two semi-circular resonators 102 and 112 configured to form a generally circular resonator configuration. The sensor 100 may also be described as having a generally circular sensor shape because the molecule recognition component layer 122 (discussed below) has a generally circular shape.

In a particularly illustrated embodiment, each of the first and second generally semi-circular resonators 102 and 112 may be formed by top electrode layers 108 and 118 and bottom electrode layers 108 and 118 sharing a generally circular shaped material layer, the bottom electrode layers each being independently generally semi-circular and different (e.g., a ring of bottom electrode material having a gap across the diameter of the circle, the gap having a width d). The layers of material of the top electrode, piezoelectric layer, bottom electrode, or any combination thereof may be patterned-or otherwise utilized using known methods including, for example, printing methods-to provide any desired shape including, for example, semi-circular, square, rectangular.

In some embodiments, at least the first resonator 102 and the second resonator 112 (and additional resonators, if present) may be electrically connected in series with each other. It is to be noted that the electrical connection of two or more resonators is not depicted in the figures. Those skilled in the art who have read the description will understand and know how to connect at least the first resonator 102 and the second resonator 112 in series. The series connection of at least the first resonator 102 and the second resonator 112 is typically such that the signal is received therefrom as if it were received from a single resonator.

A quantitative and qualitative knowledge of the resonator Q-value can be obtained by plotting on a smith chart, for an SMR resonator having an impedance equal to (or normalized to) the system impedance at the resonant frequency, the ratio of reflected energy to applied energy (i.e., the reflection coefficient) varies with frequency with one electrode grounded and the other grounded to the signal. As the frequency of the applied energy (e.g., RF signal) increases, the magnitude/phase of the SMR resonator sweeps out of a circle in a clockwise manner on the smith chart. This is called the Q-circle (Q-circle). In the case where the Q-circle first intersects the real axis (horizontal axis), this corresponds to the series resonance frequency f_s. The true impedance (as measured in ohms) is R_s. As the Q circle continues around the perimeter of the smith chart, it again intersects the real axis. The second point is marked f_pThe parallel or anti-resonant frequency of the SMR, where the Q circle intersects the real axis at a second point. At f_pThe lower true impedance is R_p。

It is generally desirable to minimize R_sSimultaneously maximize R_P. Qualitatively, the closer the Q-circle "hugs" (hugs) is to the outer edge of the smith chart, the higher the Q-factor of the device. The radius of the Q-circle of an ideal lossless resonator will be 1 and will be at the edge of the smith chart.

Among other adverse effects, the transverse mode adversely affects the quality (Q) factor of the BAW resonator device. In particular, the energy of the rayleigh-lamb mode is lost at the interface of the inactive region and the BAW resonator device. It will be appreciated that this loss of energy to the secondary oscillation mode is a loss of energy in the desired longitudinal mode, and ultimately a reduction in the Q factor. A smith chart can be used to compare the secondary oscillation modes of the resonator.

Fig. 6A to 6D show smith plan views of various resonators. The resonators that produce the smith plans seen in fig. 6A to 6D are identical except for the features specified herein. All resonators have AlN piezoelectric layers. Figure 6A shows a smith plan of a circular 900MHz resonator having a diameter of 350 μm. The parasitic resonance is evident from the multiple rings in the plan view. Figure 6B shows a smith plan of two circular 2,250MHz resonators connected in series. Each resonator has a diameter of 213 μm and between two is 42 μm. The parasitic resonance is significantly reduced compared to the resonator of fig. 6A with only a single circular resonator. Figure 6C shows a smith plan of two semi-circular 2,250MHz resonators connected in series. The resonator is placed on the planar side facing the 48 μm gap and the overall circular resonator configuration is a circle with a diameter of 350 μm. The parasitic resonance is reduced compared to the resonators of fig. 6A and 6B. Figure 6D shows a smith plan of four square 2,250MHz resonators connected in series. Each resonator has a length and width of 125 μm. The four resonators were configured in a square shape with a 42 μm gap between each resonator. The parasitic resonance is reduced compared to all resonators of fig. 6A, 6B, 6C and 6D.

In some embodiments, the disclosed sensors may also include an oxygen containing layer. The sensor 100 depicted in fig. 1A includes an oxygen containing layer 140 positioned on the second surfaces 107 and 117 of the first and second resonators 102 and 112. In some embodiments, the oxygen containing layer 140 may be present across substantially the entire sensor. In some embodiments, the oxygen containing layer may have at least

At least

At least

Or at leastIs measured. In some embodiments, the metal oxide layer can have a thickness no greater than

Not more thanNot more than

Or not more than

Is measured.

The oxygen containing layer may include oxygen atoms, compounds including oxygen atoms, or both. In some embodiments, the oxygen containing layer may be an oxide layer, or more specifically, a metal oxide layer, and may include any metal oxide. In some embodiments, the metal oxide layer may include TiO₂、SiO₂、A1₂O₃Or ZnO. In some embodiments, the metal oxide layer may comprise TiO₂. The metal oxide layer may be described as including oxygen atoms. Oxygen atoms may be used to chemically bind or bind the material of the layer deposited thereon.

The oxygen containing layer may be deposited using various methods. In some embodiments, the oxygen containing layer may be deposited using Atomic Layer Deposition (ALD). ALD may provide an oxide layer that is relatively thin, relatively uniform, relatively dense, or some combination of the others. ALD can be described as a self-limiting process that forms a thin film of material in a layer and can thus reproducibly produce a uniform and very thin film.

The sensor may also include a coupling layer. The sensor 100 disclosed in fig. 1A comprises a coupling layer 130. The coupling layer 130 may generally be described as being positioned on the oxygen containing layer 140. In some embodiments, the coupling layer may be present across substantially the entire sensor 100. In some embodiments, the coupling layer may be described as a single layer of the compound that makes up the coupling layer. In some embodiments, the coupling layer 130 may have at leastOr at least

Is measured. In some embodiments, coupling layer 130 may have a thickness no greater than

Or at least not greater than

Is measured.

In some embodiments, the coupling layer 130 may be more specifically described as a silane layer or include a silane containing composition. The silane layer can be more specifically described as being composed of a silane coupling agent. Silane coupling agents are silicon-based chemicals that contain both inorganic and organic reactivity in the same molecule. The general structure can be described as (RO)₃SiCH₂CH₂CH₂-X, wherein RO represents an inorganic reactive group or a hydrolysable group (e.g. methoxy, ethoxy, acetoxy, thiol, or acetaldehyde) and X represents a group comprising an organic reactive group (e.g. amino, methacryloxy, or epoxy) and X may also comprise an additional carbon (- (CH) s₂)_n) And may or may not include functional groups. In the sensor 100, the silane layer 130 may be used to couple the metal oxide layer 140 to the molecular recognition component layer 122.

Illustrative materials that may be used to form the silane layer 130 may include, for example, (3-aminopropyl) triethoxysilane, (3-aminopropyl) trimethoxysilane, (3-glycidoxypropyl) triethoxysilane, (3-mercaptopropyl) trimethoxysilane, (3-mercaptopropyl) triethoxysilane, trimethoxy [2- (7-oxabicyclo [4.1.0] hept-3-yl) ethyl ] silane, triethoxy [2- (7-oxabicyclo [4.1.0] hept-3-yl) ethyl ] silane, Trimethoxysilyl (trimethyoxysilyl alklyl) and aldehyderythroxysilylaldehyde (aldehyderythroxysilyl alkide). In some embodiments, the silane layer 130 may be formed by (3-glycidoxypropyl) triethoxysilane.

The sensor may also include a layer of molecular recognition components. The sensor 100 disclosed in fig. 1A includes a molecule recognition component layer 122. The molecule recognition component layer 122 may be generally described as being positioned adjacent to at least the first and second resonators, and may be more particularly described as being positioned above the coupling layer 130. In some embodiments, the molecular recognition component layer 122 may be present across substantially the entire sensor 100. In some embodiments, the molecular recognition component layer 122 may have at least

Or at leastIs measured. In some embodiments, the molecular recognition component layer 122 may have a molecular recognition component size no greater than

Or not more than

Is measured.

The molecular recognition component layer 122 may comprise any material capable of interacting with the analyte of interest in a manner that allows analysis of the analyte of interest. The molecular recognition component may include any component that selectively binds to the analyte of interest. By way of example, the molecular recognition element may be selected from the group consisting of: nucleic acids, nucleotides, nucleosides, nucleic acid analogs such as PNA and LNA molecules, proteins, peptides, antibodies including IgA, IgG, IgM, IgE, lectins, enzymes, cofactors, substrates, enzyme inhibitors, receptors, ligands, kinases, protein a, polyuridylic acid, polyanilic acid, polylysine, triazine dyes, boronic acids, thiols, heparin, polysaccharides, coomassie blue, azure a, metal binding peptides, sugars, carbohydrates, chelators, prokaryotic and eukaryotic cells. In some embodiments, antibodies may be used for the molecular recognition component, and in such embodiments, the thickness of the molecular recognition component layer 122 may be described as not less than

Or in some embodiments not less than

The molecule recognition component layer 122 may be formed on (or more specifically bonded to) the coupling layer 130 using known techniques. One or more individual elemental or chemical group (comprising two or more elements) components in the molecular recognition component layer may each be chemically bound to, for example, silane or one or more silanes in the coupling layer 130. The conditions and procedural steps for affecting this binding will be known to those skilled in the art reading the specification. It should also be noted that the molecular recognition component may be bound to the coupling layer by an additional coupling agent or component in addition to just the coupling layer itself. In some embodiments, an antibody may be used as the molecular recognition element and it may be bound to an epoxy silane that includes a coupling layer.

In some embodiments, the molecule recognition component layer 122 may have a substantially circular shape. The molecular recognition component layer 122 may be generally described as covering at least both the first and second resonators 102 and 112. The shape of the molecule recognition component layer 122 may partially define the shape of the sensor 100 (in combination with or in accordance with the resonator configuration described above). In some embodiments, the molecular recognition layer may be a shape designed to cover at least the entire surface superimposed on the area of at least the first and second resonators. In some embodiments, the molecular recognition component layer may be a shape covering more than the entire surface superimposed on the area of at least the first and second resonators. In some embodiments, the substantially circular shape of the molecule recognition component layer may be attributed, at least in part, to the process of forming the layer. Details of such procedures are described below.

As described above, the first and second resonators 102 and 112 may optionally include layers not depicted in fig. 1A. For example, a layer designed to promote adhesion between two layers, a layer designed to protect a structure, layer, or material, a layer designed to provide other functionality, or any combination thereof, may be selectively included in the first and second resonators.

Specific examples of optional additional layers may include, for example, an adhesive layer. For example, an adhesion layer can be formed on the surface of piezoelectric layers 106 and 116. In some embodiments, an adhesion layer, if included, may be used to improve adhesion between the top electrode material and the piezoelectric layer. In some embodiments, the adhesion layer, if included, can include a material that is compatible with the material of the top electrode layer, the material of the piezoelectric layer, or both. Illustrative specific materials that may be used for the adhesion layer may include, for example, titanium (Ti), or chromium (Cr). In some embodiments where the top electrode is gold, the optional additional layer may include, for example, Ti or Cr. In some embodiments, the adhesiveThe additional layer, if included, may have at least

At least

Or at least

Is measured. In some embodiments, the adhesion layer, if included, may have a thickness no greater than

Not more than

Or not more than

Is measured. In some embodiments, the adhesion layer, if included, may have an approximate thickness

Is measured.

The illustrative sensor may also include optional components not discussed above. For example, in some embodiments, the sensor may include a bragg mirror stack. In some embodiments, a bragg mirror stack, if included, may be disposed below the bottom electrodes 104 and 114 of at least both the first and second resonators. First and second resonators having a proximate configuration, such as used in the disclosed sensor, may be coupled through a substrate on which they are formed. Such coupling may be considered undesirable. The use of an optical bragg mirror stack may be used to mitigate such coupling. While it may be advantageous to mitigate such coupling by a bragg mirror stack, the bragg mirror stack may form parasitic resonances. The first and second resonators are connected in series to reduce or prevent possible parasitic resonances. The electrical and mass loading effects of the series connected first and second resonators may be substantially equal to (in some embodiments, greater than) the single resonator minus the parasitic resonance induced by the bragg mirror stack.

Also disclosed herein are assemblies or devices. The disclosed assembly may generally include at least one active sensor and at least one reference sensor. In some embodiments, the assembly may include at least one reference sensor and two or more active sensors. Such an embodiment may be advantageous in that two or more active sensors will be able to use all reference sensors. In some embodiments, the assembly may include one reference sensor and at least three (for example) active sensors. Fig. 2 depicts an assembly 200, the illustrative assembly 200 including an active sensor 250 and a reference sensor 260. The active sensor 250 includes a first resonator 102a and a second resonator 112 a. The reference sensor 260 also includes a first resonator 102b and a second resonator 112 b. The first resonator 102a, the second resonator 112a, the first resonator 102b, and the second resonator 112b each include a bottom electrode (104a, 114a, 104b, 114b), a piezoelectric layer (106a, 116a, 106b, and 116b), and a top electrode (108a, 118a, 108b, and 118 b). The features of the resonator, for example, the bottom electrode, the piezoelectric layer, and the top electrode may include those disclosed above.

In some embodiments, the at least one active sensor 250 and the at least one reference sensor 260 may, but need not, have substantially the same shape. In some embodiments, the active sensor 250 and the reference sensor 260 may both have a substantially circular sensor shape. The at least one active sensor 250 and the at least one reference sensor 260 may be spaced apart by a distance. Fig. 2B depicts the active sensor 250 and the reference sensor 260 separated by a distance D. In some embodiments, the active sensor 250 and the reference sensor 260 may be separated by a distance (D) of at least 20 μm. In some embodiments, the active sensor 250 and the reference sensor 260 may be separated by a distance (D) of at least 50 μm. In some embodiments, the active sensor 250 and the reference sensor 260 may be separated by a distance (D) of no more than 2000 μm. In some embodiments, the active sensor 250 and the reference sensor 260 may be separated by a distance (D) of no greater than 500 μm. In some embodiments including one active sensor and one reference sensor, the two sensors may be separated by a distance (D) from 150 μm to 250 μm, for example, by about 200 μm.

The assembly 200 may also include an oxygen containing layer 240 and a coupling layer 230. These layers may be substantially as described above. In some embodiments, the oxygen containing layer 240 and the coupling layer 230 may cover more than just the at least one active sensor 250 and the at least one reference sensor 260. In some embodiments, the oxygen containing layer 240 and the coupling layer 230 may cover substantially the entire surface of at least a portion of the substrate on which the at least one active sensor 250 and the at least one reference sensor 260 are positioned. The features of the oxygen containing layer 240 and the coupling layer 230 may include those described above.

The assembly 200 may include a molecular recognition component layer 209. In some embodiments, the molecular recognition component layer 209 may cover only the area located above the at least one active sensor 250. In some embodiments, the molecular recognition component layer 209 may cover more than the area overlying at least one reference sensor 260 but not over the area overlying any of the at least one reference sensors 260. In some embodiments, the molecule recognition component layer 209 may at least partially define the shape of the active sensor 250, e.g., a substantially circular shape. The characteristics of the molecular recognition component layer may include those as described above.

The assembly 200 may also include a reference bonding material layer 219. In some embodiments, the reference bonding material layer 219 may cover only the area located above the reference sensor 260. In some embodiments, the layer of reference bonding material 219 may cover more than the area overlying the at least one reference sensor 250 but not on the area overlying any of the at least one active sensor 250. In some embodiments, the reference bonding material layer 219 may at least partially define the shape of the reference sensor 260. The material forming the reference binding material layer 219 may be selected such that the material to be tested in the sample does not appreciably bind to the reference binding material layer material. In some embodiments, the molecular weight of the material forming the reference binding material layer 219 may be substantially similar to the molecular weight of the material forming the molecular recognition component layer 209. In some embodiments, the material forming the layer of reference binding material is a material that does not significantly bind to any material to be tested in the sample and has a molecular weight similar to the molecular weight of the material forming the layer of molecular recognition component. Such an embodiment should provide signals from the active sensor 250 and the reference sensor 260 that differ only by the analyte of interest in the sample.

The particular type of reference binding material used to make the layer of reference binding material may depend, at least in part, on the particular type of molecular recognition component used for the layer of molecular recognition component. One skilled in the art who has read this specification will be able to recognize the possible types of reference binding materials for the particular molecular recognition element used. In some embodiments where antibodies are used as molecular recognition components, the reference binding material may comprise, for example, comparable species/subtypes of antibodies in the sample to be tested that do not have a known specificity or specificity for materials that are known to be absent.

Also disclosed herein are methods of forming sensors. An illustrative method may include forming at least first and second resonators, depositing an oxygen-containing layer on a surface of at least the first and second resonators, forming a coupling agent layer on the oxygen-containing layer, and depositing a molecular recognition component on the coupling agent layer.

Also disclosed herein are methods of forming sensors. An illustrative method may include forming at least a first resonator having a first surface and an opposing second surface; and forming a coupling layer on the second surface of at least the first resonator; and depositing a molecular recognition component composition on the coupling layer, the molecular recognition component composition being deposited so as to form a molecular recognition component layer having a substantially circular shape covering at least the first resonator. The composition comprising the molecular recognition element may further comprise a solvent or other element designed, for example, to adjust the pH of the solution, stabilize the protein in a liquid or dry state, or a combination thereof. The composition comprising the molecular recognition element may further comprise other optional materials including, for example, buffers to help stabilize the molecular recognition element, salts, sugars, other ingredients, or any combination thereof. The solvent, once the composition comprising the molecular recognition component is deposited, can be easily allowed to evaporate based on its vapor pressure or conditions that can be controlled for controlling the evaporation rate of the solvent (temperature control, humidity control, etc.).

In some embodiments, at least the first and second resonators may be formed on a substrate, or more particularly, in some embodiments, on a silicon wafer. Any method for depositing materials such as those discussed herein for the bottom electrode, the piezoelectric layer, and the top electrode may be used to form the bottom electrode, the piezoelectric layer, and the top electrode. Illustrative types of methods can include, for example, vapor deposition methods (e.g., chemical vapor deposition methods [ e.g., Plasma Enhanced Chemical Vapor Deposition (PECVD) methods ], physical vapor deposition methods), sputtering methods (e.g., reactive sputtering methods), Atomic Layer Deposition (ALD) methods, and plate culture methods (e.g., electrochemical or electroless plating). Also, any method for representing layers in a pattern or shape may be used herein. Illustrative types of processes may include, for example, printing processes (e.g., photolithography), etching processes (e.g., milling, reactive ion etching, chemical etching), and lift-off techniques. The first and second resonators formed herein may include features such as those described above. As described above, each of the first and second resonators includes a first surface and an opposing second surface.

A next step may include depositing an oxygen containing layer, for example, depositing an oxide layer on at least the first and second resonators. More specifically, for example, an oxide layer may be deposited on the second surfaces of both the first and second resonators. In some embodiments, a single layer may be formed on the second surfaces of both the first and second resonators. In some embodiments, more than one layer may be formed to cover the second surfaces of both the first and second resonators. In some embodiments, a single deposition step may form the disclosed oxide layer, and in some embodiments, more than one deposition step may be used to form the disclosed oxide layer.

In some embodiments, the step of depositing the oxide layer may be accomplished using Atomic Layer Deposition (ALD). ALD is generally considered a thin film deposition technique that uses a continuous vapor phase chemical sequence. ALD processes typically use precursors and a layer is grown on a surface by successively exposing the surface to be covered to the precursors. Because the surface is exposed to the precursor in a continuous manner, the deposition process is self-limiting and therefore it is relatively easy to control the deposition depth. On depositing TiO₂In some embodiments, for example, Titanium Tetraisopropoxide (TTIP) or tetra-dimethyl-amino-titanium (TDMAT) may be used.

A next step may include forming a coupling layer on the oxide layer. The forming of the coupling layer on the oxide layer may generally include depositing a composition including a coupling agent on the oxide layer. Conditions that may or may not be required for the coupling agent to react with the oxide layer may depend, at least in part, on the particular coupling agent used. In some embodiments, silane materials may be used as coupling agents. The disclosed methods may also optionally include removing unbound coupling agent and other ingredients of the composition. Such optional steps may begin after the coupling agent has been given sufficient time, suitable conditions, or some combination thereof to react with the oxide layer. The optional step of removing unbound coupling agent and other components of the composition may be accomplished by, for example, washing the surface with a liquid that does not dissolve the coupling agent.

A next step may include forming a molecule recognition component layer on the coupling layer. Forming the molecule recognition component layer on the coupling layer may generally include depositing a composition including the molecule recognition component on the coupling layer. Conditions that may or may not be required for the molecular recognition component to react with the coupling layer may depend, at least in part, on the particular coupling agent and the particular molecular recognition component used. The disclosed methods may also optionally include removing unbound molecular recognition components and other components of the composition. Such optional steps may be initiated after the molecular recognition component has been given sufficient time, suitable conditions, or some combination thereof to react with the coupling agent on the surface of the oxide layer. The optional step of removing unbound molecular recognition component and other components of the composition may be accomplished by, for example, washing the surface with a liquid that does not dissolve the molecular recognition component, the coupling agent, or both.

In some embodiments, the methods disclosed herein may also include other optional steps. For example, the disclosed method may further comprise the step of electrically connecting the first and second resonators in series. Those skilled in the art who have read this specification will understand how to electrically connect the first and second resonators in series. In some embodiments, the optional step of electrically connecting the first and second resonators in series may occur prior to depositing the oxide layer, for formation of the coupling agent layer, or prior to depositing the molecular recognition component layer. In some embodiments, the optional step of electrically connecting the first and second resonators in series may occur prior to deposition of the oxide layer.

Another example of an alternative method that may be used in the disclosed method may include the step of placing a wafer. As described above, the sensors formed herein may be formed on a substrate, such as a wafer or more specifically a silicon wafer in some embodiments. The deposition process used to form the disclosed sensors can generally be performed more cost-effectively by forming multiple sensors on a single silicon wafer. After forming the plurality of first and second resonators at any point in the method, the substrate on which the plurality of first and second resonators are formed may be cut. In some embodiments, only a single portion of the substrate containing the first and second resonators may be formed by dicing. In some embodiments, a single portion of the substrate containing both the first and second resonators, e.g., the active sensor and the reference sensor as described above, may be formed by dicing. In some embodiments, the optional step of placing can occur prior to deposition of the oxide layer, prior to deposition of the coupling agent layer, or prior to deposition of the molecular recognition component layer. In some embodiments, an optional step of cutting may occur prior to deposition of the oxide layer.

Another example of optional steps that may be used in the disclosed method may include the step of mounting the sensor on an electrical connection board. As described above, the sensors formed herein may be formed on a substrate, such as a wafer or more specifically a silicon wafer in some embodiments. A wafer containing one or more sensors may be attached to the electrical connection board. The electrical connection board may also be referred to as a Printed Circuit Board (PCB). Attachment of the wafer containing the one or more sensors may involve physical attachment (e.g., with an adhesive), and electrical attachment (e.g., electrically connecting electrical contacts connected to the first and second resonators to electrical contacts on an electrical connection board through a conductive material), or a combination thereof.

An example of a particular illustrative method may include depositing a metal oxide layer, or more specifically, TiO, on a silicon wafer containing a plurality of resonant sensors by Titanium Tetraisopropoxide (TTIP) or tetra-dimethyl-amino-titanium (TDMAT) precursor at about 120 ℃ to 180 ℃ using ALD₂. The silicon wafer is then diced into sections containing the source sensor and the adjacent reference sensor. After dicing, the substrate containing the two sensors may be assembled and electrically connected to a Printed Circuit Board (PCB). The sensor-mounted PCB is then cleaned by an oxygen plasma cleaning procedure. The cleaned sensor-mounted PCB then has epoxy silane deposited thereon using a vapor deposition process (a more specific explanation of one method of performing this step may include venting the chamber, selectively raising the temperature of the chamber, allowing the epoxy silane to volatilize and soak into the environment of the chamber, and then allowing the epoxy silane to deposit on the sensor-mounted PCB). The sensor-mounted PCB coated with epoxy silane may then have an antibody containing a buffer composition comprising sucrose stained thereon. The spotted sensor-mounted PCB was then placed in a temperature controlled environment and held at about 37 c for about 30 minutes.

In the foregoing detailed description, numerous specific embodiments of ingredients, compositions, products and methods are disclosed. It is to be understood that other embodiments are contemplated and may be made without departing from the scope or spirit of the present invention. Therefore, the following detailed description is not to be taken in a limiting sense.

All scientific and technical terms used herein have the meanings commonly used in the art unless otherwise specified. The definitions provided herein are to facilitate understanding of certain terms used frequently herein and are not meant to limit the scope of the present disclosure.

As used in this specification and the appended claims, the singular forms "a", "an" and "the" include embodiments having plural referents, unless the content clearly dictates otherwise.

As used in this specification and the appended claims, the term "or" is generally employed in its sense including "and/or" unless the content clearly dictates otherwise. The term "and/or" refers to one or all of the listed elements or a combination of any two or more of the listed elements.

As used herein, "present", "including", "performing", "including", "performing", "including", "performing", "in an open sense", and generally means "including, but not limited to". It should be understood that "consisting essentially of … …", "consisting of", and the like, are inclusive of "comprising" and the like. As used herein, "consisting essentially of," when it refers to a composition, product, method, or the like, means that the composition, product, method, or the like, is limited to the recited ingredients and any other ingredients that do not materially affect the basic and novel characteristic(s) of the composition, product, method, or the like.

The words "preferred" and "preferably" refer to embodiments of the invention that may provide certain benefits under certain circumstances. However, other embodiments may be preferred under the same or other circumstances. Furthermore, the recitation of one or more preferred embodiments does not imply that other embodiments are not useful, and is not intended to exclude other embodiments from the scope of the disclosure, including the claims.

Also herein, the recitation of numerical ranges by endpoints includes all numbers subsumed within that range (e.g. 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, 5, etc., or 10 or less includes 10, 9.4, 7.6, 5, 4.3, 2.9, 1.62, 0.3, etc.). Where a range of values is "up to" a particular value, that value is included in the range.

Any directions referenced herein, such as "top," "bottom," "left," "right," "up," "down," and other directions and orientations, are described herein with reference to the drawings for clarity and are not limiting of the actual device or system or use of the device or system. The devices or systems described herein may be used in a number of directions and orientations.

Thus, embodiments of a two-part assembly are disclosed. The above-described embodiments and other embodiments are within the scope of the following claims. Those skilled in the art will appreciate that the present invention may be practiced with embodiments other than those disclosed. The disclosed embodiments are presented for illustrative and non-limiting purposes.