阅读说明：本技术 半导体装置和光电探测系统 (Semiconductor device and photodetection system ) 是由 徐青 张玺 王麟 尼古拉达申佐 谢庆国 于 2020-05-28 设计创作，主要内容包括：本申请公开了一种半导体装置和光电探测系统,该半导体装置可以包括：衬底；外延层,其位于所述衬底的上方,并且与所述衬底均呈第一导电类型；第一掺杂区,其形成于所述外延层中的远离所述衬底的一侧,呈与所述第一导电类型相反的第二导电类型,并且通过所述第一掺杂区形成所述半导体装置的输出端；第二掺杂区,其形成于所述一侧并呈所述第二导电类型；第三掺杂区,其形成于所述一侧并呈所述第一导电类型,其中,所述第二掺杂区位于所述第一掺杂区与所述第三掺杂区之间,并且所述衬底、所述第一掺杂区至所述第三掺杂区的掺杂浓度均大于所述外延层的掺杂浓度。通过利用本申请提供的技术方案,可以提高对波长较长的光子的探测效率。(The application discloses semiconductor device and photoelectric detection system, this semiconductor device can include: a substrate; the epitaxial layer is positioned above the substrate and is of a first conduction type with the substrate; the first doped region is formed on one side, far away from the substrate, of the epitaxial layer, is of a second conductivity type opposite to the first conductivity type, and forms an output end of the semiconductor device through the first doped region; a second doped region formed at the one side and having the second conductivity type; and a third doped region formed at the one side and having the first conductivity type, wherein the second doped region is located between the first doped region and the third doped region, and the doping concentrations of the substrate, the first doped region and the third doped region are all greater than the doping concentration of the epitaxial layer. By utilizing the technical scheme provided by the application, the detection efficiency of photons with longer wavelength can be improved.)

1. A semiconductor device, characterized in that the semiconductor device comprises:

a substrate;

the epitaxial layer is positioned above the substrate and is of a first conduction type with the substrate;

the first doped region is formed on one side, far away from the substrate, of the epitaxial layer, is of a second conductivity type opposite to the first conductivity type, and forms an output end of the semiconductor device through the first doped region;

a second doped region formed at the one side and having the second conductivity type;

a third doped region formed at the one side and having the first conductivity type,

the second doped region is located between the first doped region and the third doped region, and the doping concentration of the substrate, the first doped region, the second doped region and the third doped region is greater than that of the epitaxial layer.

2. The semiconductor device according to claim 1, wherein a first depletion region in a first PN junction formed between the first doped region and a corresponding region in the substrate and the epitaxial layer below the first doped region and/or a second depletion region in a second PN junction formed between the second doped region and a corresponding region in the substrate and the epitaxial layer below the second doped region covers at least a portion of the epitaxial layer when the semiconductor device is in an operating state.

3. The semiconductor device according to claim 2, wherein the first depletion region and the second depletion region cover to a bottom of the epitaxial layer.

4. The semiconductor device according to claim 1, wherein an isolation region is further formed in the epitaxial layer on a side away from the substrate to separate the first doped region, the second doped region, and the third doped region.

5. The semiconductor device of claim 4, wherein each of the isolation regions is separated from or coupled to the first doped region, the second doped region, or the third doped region on a side thereof.

6. The semiconductor device according to claim 1, wherein a buried layer of the first conductivity type is formed in the epitaxial layer below at least one of the first doped region and/or at least one of the second doped regions, and a doping concentration of the buried layer is greater than a doping concentration of the epitaxial layer and less than a doping concentration of the substrate and the second doped region.

7. The semiconductor device of claim 6, wherein each buried layer is separate from or coupled to the corresponding first doped region or second doped region.

8. The semiconductor device according to claim 1, wherein a corresponding well region is formed in the epitaxial layer outside at least one of the first doped region, the second doped region, and the third doped region so as to surround at least a portion of the corresponding doped region therein, and a doping concentration of the well region is lower than that of the corresponding doped region.

9. The semiconductor device according to claim 1, wherein the substrate and the epitaxial layer are made of a simple substance of a group iva element or a compound semiconductor material.

10. The semiconductor device according to claim 9, wherein the substrate and the epitaxial layer are made of silicon, germanium, or silicon carbide.

11. The semiconductor device according to claim 1, wherein a thickness of the epitaxial layer is 1 to 10 μm.

12. The semiconductor device of claim 1, wherein the third doped regions are located at both side edges of the epitaxial layer.

13. A photodetection system, characterized in that the photodetection system comprises a semiconductor device according to any of the claims 1-12.

Technical Field

The present disclosure relates to semiconductor technologies, and more particularly, to a semiconductor device and a photodetection system.

Background

The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.

The low-flux photon detection technique is one that can detect lower luminous flux densities (e.g., 10)^-19～10^-6W/mm²) The technology for photon detection of optical signals of (a) can be applied to many fields, for example, medical imaging (particularly, Positron Emission Tomography (PET)), homeland security, high-energy physical experiments, and other imaging key fields.

In the field of low-flux photon detection technology, Silicon photomultipliers (sipms for short) have received great attention in recent years due to their advantages of high detection efficiency, excellent single photon response and resolution capability, small volume, easy integration, low working voltage, no magnetic field interference, good reliability, low cost, and the like. The cross-sectional structure of a conventional silicon photomultiplier is shown in fig. 1, and mainly includes: the semiconductor device comprises a P-type substrate or an epitaxial layer, a plurality of N Wells (NWELLs) and P + type doped regions, wherein Deep N Wells (DNW) are formed on the P-type substrate or the epitaxial layer, a plurality of N Wells (NWELL) are formed in the middle of the DNW, the P + type doped regions are formed above the NWELL and are separated by Shallow Trench Isolation (STI), and the NWELL and the N + type doped regions are formed at the edge of the DNW; and a substrate electrode composed of a P-well (PWELL) and a P + -type doped region formed outside the P-type substrate/epitaxial layer. When the SiPM is in a working state, the reverse bias voltage of the P +/NWELL junction is larger than the breakdown voltage of the P +/NWELL junction, so that a depletion region is formed, when photons are incident from the top, photogenerated carriers are mainly absorbed and formed in the depletion region, the avalanche breakdown effect of a high electric field region in the depletion region is triggered, and the high electric field region is quenched by an external quenching resistor, so that a current pulse signal responding to a single photon is generated.

In the process of implementing the present application, the inventor finds that at least the following problems exist in the prior art:

the PN junction in the conventional silicon photomultiplier generally comprises a high-concentration P (or N) -type doped region close to the surface of a silicon material and a lower-doped N (or P) well located below the high-concentration P (or N) -type doped region, and has a shallow junction depth and a narrow depletion region width, so that the conventional silicon photomultiplier has a high detection efficiency for blue-violet light with a short wavelength, but has a low detection efficiency for photons with a long wavelength (e.g., red light and near-infrared light).

Disclosure of Invention

It is an object of embodiments of the present application to provide a semiconductor device and a photodetection system to improve the detection efficiency of photons having a longer wavelength.

In order to solve the above technical problem, an embodiment of the present application provides a semiconductor device, which may include:

a substrate;

the epitaxial layer is positioned above the substrate and is of a first conduction type with the substrate;

the first doped region is formed on one side, far away from the substrate, of the epitaxial layer, is of a second conductivity type opposite to the first conductivity type, and forms an output end of the semiconductor device through the first doped region;

a second doped region formed at the one side and having the second conductivity type;

a third doped region formed at the one side and having the first conductivity type,

the second doped region is located between the first doped region and the third doped region, and the doping concentration of the substrate, the first doped region, the second doped region and the third doped region is greater than that of the epitaxial layer.

Optionally, when the semiconductor device is in an operating state, a first depletion region in a first PN junction formed between the first doped region and a corresponding region in the substrate and the epitaxial layer below the first doped region and/or a second depletion region in a second PN junction formed between the second doped region and a corresponding region in the substrate and the epitaxial layer below the second doped region covers at least a portion of the epitaxial layer.

Optionally, the first depletion region and the second depletion region cover to the bottom of the epitaxial layer.

Optionally, an isolation region is further formed in the epitaxial layer on a side away from the substrate to separate the first doped region, the second doped region and the third doped region.

Optionally, each of the isolation regions is separated from or coupled to the first doped region, the second doped region, or the third doped region on the side thereof.

Optionally, a buried layer of the first conductivity type is formed in the epitaxial layer below at least one of the first doped region and/or at least one of the second doped region, and a doping concentration of the buried layer is greater than a doping concentration of the epitaxial layer and less than a doping concentration of the substrate and the second doped region.

Optionally, each of the buried layers is separate from or coupled to the corresponding first doped region or the second doped region.

Optionally, a corresponding well region is formed in the epitaxial layer outside at least one of the first doped region, the second doped region and the third doped region to surround at least a portion of the corresponding doped region, and the doping concentration of the well region is lower than that of the corresponding doped region.

Optionally, the substrate and the epitaxial layer are made of a simple substance or compound semiconductor material of a group iva element.

Optionally, the substrate and the epitaxial layer are made of silicon, germanium or silicon carbide.

Optionally, the thickness of the epitaxial layer is 1-10 microns.

Optionally, the third doped regions are located at two side edges of the epitaxial layer.

The embodiment of the application also provides a photoelectric detection system which can comprise the semiconductor device.

As can be seen from the above technical solutions provided by the embodiments of the present application, in the semiconductor device provided by the embodiments of the present application, the first doped region, the second doped region and the third doped region of the first conductivity type are formed on the outer surface of the side of the epitaxial layer away from the substrate, the output end of the semiconductor device is formed by the first doped region, and the first doped region and the third doped region are separated by the second doped region, so that compared with a case where the first doped region and the third doped region are adjacent to each other, the width of the first depletion region in the first PN junction formed between the first doped region and the corresponding region in the epitaxial layer and the substrate when the semiconductor device is in an operating state can be increased, and the influence of the internal noise of the device on the first PN junction can be reduced, thereby improving the detection efficiency of photons with longer wavelengths.

Drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below, it is obvious that the drawings in the following description are only some embodiments described in the present application, and for those skilled in the art, other drawings can be obtained according to the drawings without any creative effort.

FIG. 1 is a schematic diagram of a prior art silicon photomultiplier structure;

fig. 2 is a schematic structural diagram of a semiconductor device according to an embodiment of the present application;

fig. 3 is a schematic structural diagram of a semiconductor device according to another embodiment of the present application;

fig. 4 is a schematic structural diagram of a semiconductor device according to another embodiment of the present application.

Detailed Description

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only used for explaining a part of the embodiments of the present application, but not all embodiments, and are not intended to limit the scope of the present application or the claims. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

It will be understood that when an element is referred to as being "disposed on" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected/coupled" to another element, it can be directly connected/coupled to the other element or intervening elements may also be present. The term "connected/coupled" as used herein may include electrical and/or mechanical physical connections/couplings. The term "comprises/comprising" as used herein refers to the presence of features, steps or elements, but does not preclude the presence or addition of one or more other features, steps or elements. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items. The terms "above" and "below" as used herein are relative terms only, and upper may also refer to lower and vice versa, depending on the different viewing orientations or placement positions.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

In the description of the present application, the terms "first," "second," "third," and the like are used for descriptive purposes only and to distinguish similar objects, and there is no order of precedence between them or it is understood that relative importance is indicated or implied. In addition, in the description of the present application, "a plurality" means two or more unless otherwise specified.

In the description of the present application, the first conductivity type may refer to P-type doping, which is mainly conducted by holes, the second conductivity type may refer to N-type doping, which is mainly conducted by electrons, and alternatively, the first conductivity type may refer to N-type doping and the second conductivity type may refer to P-type doping. Additionally, "P +" and "P-" may refer to relatively higher and lower doping concentrations, respectively, as compared to the doping concentration of a P-type doped region, while "N +" and "N-" may refer to relatively higher and lower doping concentrations, respectively, as compared to the doping concentration of an N-type doped region, e.g., the doping concentrations of the P + -type and N + -type doped layers/regions may be 1x10¹⁹～1x10²¹cm^-3The doping concentration of the P-type and N-type doped layers/regions may be 1x10¹⁶～1x10¹⁸cm^-3. Doped regions or doped layers having the same conductivity type may have the same or different doping concentrations, or doped regions or doped layers having different conductivity types may have the same or different doping concentrations, unless otherwise specified.

The semiconductor device and the photodetection system for photon detection provided by the embodiments of the present application are described in detail below with reference to the accompanying drawings.

As shown in fig. 2, an embodiment of the present application provides a semiconductor device, which may include: a substrate 110; an epitaxial layer 120 which is located above the substrate and which is of the first conductivity type with the substrate 110; a first doped region 130 formed in the epitaxial layer 120 on a side thereof away from the substrate 110, having a second conductivity type opposite to the first conductivity type, and through which an output terminal of the semiconductor device can be formed; a second doped region 140 also formed in the epitaxial layer 120 on a side thereof remote from the substrate 110 and of a second conductivity type; and a third doped region 150 also formed in the epitaxial layer 120 on a side thereof remote from the substrate 110 and of the first conductivity type, wherein the second doped region 140 is located between the first doped region 130 and the third doped region 150 to space them apart. In addition, the doping concentrations of the substrate 110, the first doping region 130, the second doping region 140 and the third doping region 150 may be all greater than the doping concentration of the epitaxial layer 120, and the doping concentrations of the substrate 110, the first doping region 130, the second doping region 140 and the third doping region 150 may be the same or different.

The substrate 110 may be an N-type doped substrate or a P-type doped substrate made of a first doping material, and preferably, an N + -type or a P + -type doped substrate, whose doping concentration is generally high, and whose doping concentration may be the same as or different from that of the second doping region 140. The epitaxial layer 120 may be an N-type doped layer or a P-type doped layer made of the first doping material, and the thickness thereof is generally 1 to 10 μm. The first doping material may be a simple substance of a group iva element or a compound semiconductor material, such as silicon, germanium, silicon carbide, or the like, but is not limited thereto. By forming the substrate 110 and the epitaxial layer 120 of germanium or silicon carbide, the detection efficiency of visible light (e.g., red light) and near-infrared light having a longer wavelength can be improved.

The first doped region 130 and the second doped region 140 may be filled with a second doping material having a conductivity type opposite to that of the first doping material, and the doping concentrations inside the two may be the same or different. The third doped region 150 may be filled with the first doped material and may be located at two side edges of the epitaxial layer 120, so that more first doped regions 130 may be formed on the epitaxial layer 120, and the photon detection efficiency may be improved. When the semiconductor device is in an operating state (i.e., a power-on state), a first depletion region in a first PN junction formed between the first doped region 130 and a corresponding region within the substrate 110 and the epitaxial layer 120 that is located below the first doped region 130 (as shown by the dashed region in fig. 2) and/or a second depletion region in a second PN junction formed between the second doped region 140 and a corresponding region within the substrate 110 and the epitaxial layer 120 that is located below the second doped region 140 (as shown by the dashed region in fig. 2) may cover at least a portion of the epitaxial layer 120, which may increase the depth of the first and second PN junctions formed. Preferably, the first depletion region and the second depletion region may cover the bottom of the epitaxial layer 120, that is, the epitaxial layer 120 is completely depleted in the depth direction, which may form a conductive path inside the semiconductor device through the third doped region 150, the epitaxial layer 120, the substrate 110, the epitaxial layer 120 to the first doped region 130, thereby increasing the depth of the formed PN junction and increasing the width of the depletion region inside the PN junction, thereby increasing the effective absorption depth range of photons, improving the detection efficiency of photons with longer wavelengths (e.g., red light or near infrared light), and forming an electric field inside the semiconductor device with higher uniformity in the horizontal direction, thereby reducing dark count pulses caused by local high electric fields. In addition, the first depletion region and/or the second depletion region formed may also extend to the substrate 110.

In addition to the first to third doped regions 130 to 150, at least one isolation region 160 (e.g., STI region) may be formed in the epitaxial layer 120 on a side away from the substrate 110 to space the first doped region 130, the second doped region 140, and the third doped region 150 two by two. The isolation regions 160 may be separated from the first doped region 130, the second doped region 140, or the third doped region 150 on the side thereof (as shown in fig. 2) to reduce noise, or may be coupled to the first doped region 130, the second doped region 140, or the third doped region 150 on the side thereof (as shown in fig. 3) to improve electrical performance.

In addition, buried layers 170 (e.g., P-type buried layers or N-type buried layers) of the first conductivity type may be formed in the epitaxial layer 120 under at least one of the first doped regions 130 (preferably, all of the first doped regions 130), the buried layers 170 may be respectively located at sides near the corresponding first doped regions 130, and the doping concentration of the buried layers 170 may be greater than that of the epitaxial layer 120 and less than that of the substrate 110 and the third doped regions 150. Each buried layer 170 may be separated from (as shown in fig. 2) or coupled to (as shown in fig. 3) the first doped region 130 located above it to reduce noise or improve electrical performance. By forming the buried layer 170 in the epitaxial layer 120, the width of the first depletion region in the formed first PN junction can be further increased, so that the photon absorption depth range and the photon detection efficiency can be improved. Furthermore, a buried layer 170 may also be formed in the epitaxial layer 120 below at least one second doped region 140 (preferably all second doped regions 140).

In addition, a corresponding well region may be further formed in the epitaxial layer 120 outside at least one of the first doped region 130, the second doped region 140, and the third doped region 150 to surround at least a portion of the corresponding doped region (the first doped region 130, the second doped region 140, or the third doped region 150), and the well region may have a doping concentration lower than that of the corresponding doped region and each of the well regions may have the same conductivity type as the corresponding doped region. For example, as shown in fig. 4, a first well region 180 of the second conductivity type may be formed in the epitaxial layer 120 outside the first doped region 130, and the first well region 180 may enclose at least a portion of the first doped region 130 therein to form protection for the first doped region 130. The first well region 180 may be located at a lower side between the first doped region 130 and the isolation region 160, and the doping concentration of the first well region 180 may be lower than that of the first doped region 130. A second well region 141 of the second conductivity type may also be formed within the epitaxial layer 120 outside the second doped region 140 to enclose at least a portion of the second doped region 140 therein to form a protection for the second doped region 140. The doping concentration of the second well region 141 may be lower than that of the second doping region 140, and it may be the same as the first well region 180.

For another example, as shown in fig. 2-4, a third well region 190 of the first conductivity type may be formed in the epitaxial layer 120 outside the third doped region 150, and the third well region 190 may enclose at least a portion of the third doped region 150 therein to enhance the conductivity between the third doped region 150 and the substrate 110. The doping concentration of the third well region 190 may be lower than the doping concentration of the third doped region 150. The third doped region 150 and the third well region 190 may constitute one electrode of the semiconductor device. For example, when the third doped region 150 is a P + -type doped region and the third well region 190 is a P-well, they may constitute an anode, and when the third doped region 150 is an N + -type doped region and the third well region 190 is an N-well, they may constitute a cathode. In addition, another electrode of the semiconductor device may be formed through the first doping region 130 to serve as an output terminal of the semiconductor device (not shown). A bias voltage may be provided through the two electrodes to a conductive path formed within the semiconductor device for photon detection. As to how the electrode is formed on the doped region, reference may be made to the corresponding description in the prior art, which is not repeated here.

As can be seen from the above description, in the embodiment of the present application, the first doping region and the second doping region of the second conductivity type and the third doping region of the first conductivity type located at two sides of the second doping region are formed on the outer surface of the side of the epitaxial layer away from the substrate, so that the first doping region and the third doping region are separated by the second doping region, and therefore, compared with a case where the first doping region and the third doping region are adjacent to each other, the width of the first depletion region in the first PN junction formed between the first doping region and the corresponding region in the epitaxial layer and the substrate when the semiconductor device is in an operating state can be increased, and the influence of internal noise of the device on the first PN junction can be reduced, so that the detection efficiency of photons with longer wavelength can be improved. In addition, when the semiconductor device is in an operating state, depletion regions in the first PN junction and the second PN junction formed in corresponding regions in the substrate and the epitaxial layer and located below the first doped region and the second doped region can cover the bottom of the epitaxial layer, so that a conductive path formed by the third doped region, the epitaxial layer, the substrate, the epitaxial layer and the first doped region can be formed, the depth of the first PN junction and the width of the first depletion region can be further improved, and the photon detection efficiency can be further improved.

In addition, the present application provides another photodetection system, which may include the semiconductor devices described in all the above embodiments. The photodetection system may detect photons emitted from a target object (e.g., a patient or an animal injected with a tracer, etc.) using the semiconductor device and process the photon data detected by the semiconductor device to obtain corresponding information of the target object.

For a description of the other components of the photo detection system, reference may be made to the prior art, which is not described in detail herein.

The systems, devices, modules, units, etc. set forth in the above embodiments may be embodied as chips and/or entities (e.g., discrete components) or as products having certain functions. For convenience of description, the above devices are described separately in terms of functional divisions into various layers. Of course, the functions of the layers may be integrated into one or more chips when the embodiments of the present application are implemented.

While the present application provides the components described in the embodiments or figures above, more or fewer components may be included in the apparatus based on conventional or non-inventive efforts. The embodiments in the present specification are described in a progressive manner, and the same and similar parts among the embodiments are referred to each other, and each embodiment focuses on the differences from the other embodiments.

The embodiments described above are described in order to enable those skilled in the art to understand and use the present application. It will be readily apparent to those skilled in the art that various modifications to these embodiments may be made, and the generic principles described herein may be applied to other embodiments without the use of the inventive faculty. Therefore, the present application is not limited to the above embodiments, and those skilled in the art should make improvements and modifications within the scope of the present application based on the disclosure of the present application.