阅读说明：本技术 一种新型声表面波传感器 (Novel surface acoustic wave sensor ) 是由 李卫 潘沛锋 姚铖昊 徐强 于 2019-09-24 设计创作，主要内容包括：本发明公开了一种新型声表面波传感器,采用钽酸锂材料制成声表面波传感器,产生水平剪切波；在声表面波传感器的压电基板上安装叉指式换能器电极,并在声表面波传感器表面镀一层与波传播方向垂直的二氧化硅脊阵列,所述叉指式换能器电极、二氧化硅脊阵列间隔设置。本发明利用了钽酸锂产生的水平剪切波的特点,利用在发射端和接收端叉指电极之间的感应区增加协助其振动的二氧化硅阵列,减少该波在传播过程中在垂直方向上的损耗,并利用其共振效应使得声表面波在传播时集中在表面,减少垂直方向上传播的损耗,提升压电介质的应变产生电位移,进而改善其性能。(The invention discloses a novel surface acoustic wave sensor, which is characterized in that a lithium tantalate material is adopted to manufacture the surface acoustic wave sensor to generate horizontal shear waves; an interdigital transducer electrode is arranged on a piezoelectric substrate of the surface acoustic wave sensor, a layer of silicon dioxide ridge array perpendicular to the wave propagation direction is plated on the surface of the surface acoustic wave sensor, and the interdigital transducer electrode and the silicon dioxide ridge array are arranged at intervals. The invention utilizes the characteristics of horizontal shear waves generated by lithium tantalate, and utilizes the fact that the induction area between the interdigital electrodes of the transmitting end and the receiving end is added with the silicon dioxide array for assisting the vibration of the interdigital electrodes, so that the loss of the waves in the vertical direction in the transmission process is reduced, the resonance effect of the waves is utilized to enable surface acoustic waves to be concentrated on the surface in the transmission process, the transmission loss in the vertical direction is reduced, the strain of the piezoelectric medium is promoted to generate electric displacement, and the performance of the piezoelectric medium is improved.)

1. A novel surface acoustic wave sensor is characterized in that: a lithium tantalate material is adopted to manufacture the surface acoustic wave sensor to generate horizontal shear waves; an interdigital transducer electrode is arranged on a piezoelectric substrate of the surface acoustic wave sensor, a layer of silicon dioxide ridge array perpendicular to the wave propagation direction is plated on the surface of the surface acoustic wave sensor, and the interdigital transducer electrode and the silicon dioxide ridge array are arranged at intervals.

2. A novel surface acoustic wave sensor as set forth in claim 1, wherein: the silicon dioxide ridge array is formed by a plurality of silicon dioxide strips with the width of 3 mu m at intervals of 3 mu m, the lengths of the silicon dioxide strips and the interdigital transducer electrodes are equal, and the height of the silicon dioxide strips is 0.05 mu m-3.5 mu m.

3. A novel surface acoustic wave sensor as set forth in claim 1, wherein: the outer edge distance between two adjacent interdigital transducer electrodes and the silicon dioxide ridge array is 3 mu m.

4. A novel surface acoustic wave sensor as set forth in claim 1, wherein: mass-free input and output interdigital transducer electrodes of aluminum with zero thickness and 3 μm width were mounted on a piezoelectric substrate.

5. A novel surface acoustic wave sensor as set forth in claim 1, wherein: the center-to-center spacing between adjacent interdigital transducer electrodes is 5 lambda, lambda being the wavelength.

6. A novel surface acoustic wave sensor as set forth in claim 1, wherein: the surface acoustic wave sensor generates a surface acoustic wave having a wavelength λ of 12 μm.

Technical Field

The invention relates to a structural design of a surface acoustic wave sensor. The novel surface acoustic wave structure that designs is applicable to if gas sensor among the most surface acoustic wave sensor, biosensor etc. belongs to the semiconductor sensor field.

Background

Surface Acoustic Wave (SAW) devices are composed of interleaved electrodes,the interdigitated electrodes are referred to as interdigital transducers (IDTs) that are lithographically patterned on a piezoelectric layer or substrate. Application of a time-varying electrical signal to the interdigital transducer results in launching a surface wave from either side of the interdigital transducer due to the inverse piezoelectric effect. The velocity and mode of the generated surface wave depend on the orientation of the piezoelectric crystal used as the substrate. The speed of the surface acoustic wave is 10 of the electromagnetic wave^-5Multiple times and it enables the design of small wavelength compact devices operating at high frequencies at low power levels. Since the energy of the surface acoustic wave is localized to the surface, its attenuation is very small compared to an electromagnetic wave propagating at the same frequency.

Surface acoustic wave devices are used in the design of RF filters, analog signal processing components, correlators, gyroscopes, and sensors. Gas sensors based on the surface acoustic wave principle provide a cost effective, label free and direct means of detection of gas analytes. Any disturbance occurring on the surface of the device due to mass loading of the analyte produces a change in the frequency or velocity of the waves, which can be monitored and measured in real time using electronics such as a network analyzer.

Disclosure of Invention

The invention utilizes the characteristics of horizontal shear waves generated by lithium tantalate, and utilizes the fact that the induction area between the interdigital electrodes of the transmitting end and the receiving end is added with the silicon dioxide array for assisting the vibration of the interdigital electrodes, so that the loss of the waves in the vertical direction in the transmission process is reduced, the resonance effect of the waves is utilized to enable surface acoustic waves to be concentrated on the surface in the transmission process, the transmission loss in the vertical direction is reduced, the strain of the piezoelectric medium is promoted to generate electric displacement, and the performance of the piezoelectric medium is improved.

The simulation of the invention adopts the following technical scheme.

A novel surface acoustic wave sensor is made of lithium tantalate materials and generates horizontal shear waves; an interdigital transducer electrode is arranged on a piezoelectric substrate of the surface acoustic wave sensor, a layer of silicon dioxide ridge array perpendicular to the wave propagation direction is plated on the surface of the surface acoustic wave sensor, and the interdigital transducer electrode and the silicon dioxide ridge array are arranged at intervals.

Furthermore, the silicon dioxide ridge array is formed by a plurality of silicon dioxide strips with the width of 3 mu m at intervals of 3 mu m, the length of the silicon dioxide strips is equal to that of the interdigital transducer electrodes, and the height of the silicon dioxide strips is 0.05 mu m-3.5 mu m.

Further, the distance between the outer edges of the adjacent interdigital transducer electrodes and the silicon dioxide ridge array is 3 μm.

Further, mass-free input and output interdigital transducer electrodes of aluminum having a zero thickness and a width of 3 μm are mounted on the piezoelectric substrate.

Further, the center-to-center distance between adjacent interdigital transducer electrodes is 5 λ, λ being the wavelength.

Further, the surface acoustic wave sensor generates a surface acoustic wave having a wavelength λ of 12 μm. The invention is based on the new surface acoustic wave sensor and is characterized in that:

the novel surface acoustic wave sensor adopts lithium tantalate material, generates horizontal shear wave, and is plated with a layer of silicon dioxide ridge array vertical to the wave propagation direction on the surface. Horizontal shear waves can be concentrated on the surface by the silicon dioxide ridge array, and loss in the propagation process is reduced. The surface acoustic wave device can obtain larger displacement change in the working process, namely, the phase change with larger sensitivity can be detected.

Compared with the prior art, the invention has the following outstanding advantages:

1. the process flow is simple, and only a layer of silicon dioxide structure needs to be added on the original basis.

2. The performance is improved in a certain space.

3. Low cost, stable processing technology and easy batch production.

Drawings

Fig. 1 is a schematic structural view of the present invention.

FIG. 2 is a schematic diagram of a work plane established during simulation in accordance with the present invention.

FIG. 3 is a 3D simulation diagram of the present invention.

Fig. 4-6 are stress plots for 3D simulations at 5ns, 10ns, and 15 ns.

Fig. 7 is the input and output voltages when the silicon dioxide array is 0.5 microns.

Fig. 8 is the electrical shift when the silicon dioxide array is 0.5 microns.

Fig. 9 is a comparison of the electrical displacement when the silica array was 1.1 micron, 1.55 micron, 1.95 micron.

FIG. 10 is a graph comparing the difference in electrical displacement for silicon dioxide arrays from 0.05 to 3.5, and shows that the effect is better at 1.1 microns.

Detailed Description