Photoelectric detection device
By introducing a stress source layer into the silicon-based germanium avalanche detection device, the light absorption zone layer has transformed from an indirect bandgap structure to a direct bandgap structure, which solves the problem of low response rate between the low transmission loss optical bands by traditional detectors, and improves the The sensitivity and response performance of the detector are achieved.
Patent Information
- Application Number
- CN202323577526.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2023-12-26
- Publication Date
- 2025-02-25
- Estimated Expiration
- 2033-12-26
AI Technical Summary
The traditional silicon-based germanium avalanche detector has a low response rate between the low transmission loss optical bands because the absorption coefficient of germanium has dropped sharply from 1.55μm.
By covering the stress source layer on the photodetection device layer, stress is transmitted to the light absorption zone layer, causing it to generate tensile strain, thereby converting into a direct band gap structure and improving the absorption coefficient.
The sensitivity, high-band response rate and detection performance of the photodetector are improved, the response wavelength is extended, and the carrier transmission time and 3dB bandwidth are reduced.
Smart Images
Figure CN222532119U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of semiconductor integrated circuits, in particular to a photoelectric detection device. Background Art
[0002] Germanium can absorb near-infrared light, but because germanium is an indirect bandgap semiconductor, its absorption coefficient drops sharply from 1.55μm due to its energy band structure, resulting in a low response rate of traditional silicon-based germanium avalanche detectors in low transmission loss optical bands. In order to enhance light absorption, surface luminescent avalanche detectors usually use thick germanium absorption layers. However, thick germanium absorption layers will lead to increased carrier transmission time and reduced 3dB bandwidth. Utility Model Content
[0003] The purpose of the utility model is to overcome the above-mentioned defects in the prior art and provide a photoelectric detection device.
[0004] To achieve the above purpose, the technical solution of the utility model is as follows:
[0005] The utility model provides a photoelectric detection device, comprising:
[0006] A photoelectric detection device layer is arranged on a substrate, and a stress source layer is coated on the photoelectric detection device layer, the photoelectric detection device layer is provided with a light absorption region layer, and the stress source layer is used to provide stress to the light absorption region layer so that the light absorption region layer generates corresponding tensile strain, so that the light absorption region layer is transformed from having an indirect band gap structure to a direct band gap structure.
[0007] Furthermore, the photoelectric detection device layer is also coated with an anti-reflection layer, and the stress source layer also serves as the anti-reflection layer.
[0008] Furthermore, the photoelectric detection device includes a silicon-based germanium avalanche detector coated with the stressor layer.
[0009] Further, a first substrate layer is provided on the substrate, and the photodetection device layer includes a first contact area of a first conductivity type provided in sequence on the surface of the first substrate layer, a multiplication area layer provided on the first contact area, a second contact area of a second conductivity type provided on the surface of the multiplication area layer, the light absorption area layer provided on the second contact area, and a third contact area of a second conductivity type provided on the surface of the light absorption area layer, and the stress source layer is coated on the surface and side surfaces of the light absorption area layer including the third contact area and on the side surfaces of the multiplication area layer including the second contact area.
[0010] Furthermore, the stressor layer also covers the surface of the first contact area.
[0011] Further, the first conductivity type is one of N-type and P-type, and the second conductivity type is the other of N-type and P-type.
[0012] Further, the first contact region includes an N-type first doping region, the second contact region includes a P-type second doping region, and the third contact region includes a P-type third doping region.
[0013] Further, the first contact region includes a P-type first doping region, the second contact region includes an N-type second doping region, and the third contact region includes an N-type third doping region.
[0014] Furthermore, it also includes: a plurality of contact electrodes, each of the contact electrodes passes through the stress source layer and is correspondingly connected to the first contact area and the third contact area outside the side surface of the multiplication area layer.
[0015] Furthermore, a dielectric isolation layer and a second substrate layer are provided on the substrate. The dielectric isolation layer is provided on a surface of the first substrate layer facing away from the first contact area, and the second substrate layer is provided on a surface of the dielectric isolation layer facing away from the first substrate layer.
[0016] It can be seen from the above technical scheme that the utility model coats the stress source layer on the photoelectric detection device layer, and transmits stress to the light absorption zone layer, so that the light absorption zone layer obtains tensile strain, so that the light absorption zone layer changes from an indirect band gap structure to a direct band gap structure, thereby increasing the absorption coefficient in the response band of the light absorption zone layer, and the response wavelength can also be extended accordingly. Furthermore, the silicon-based germanium avalanche detector coated with a stress source layer (such as a silicon nitride layer) can solve the problem that the absorption coefficient of the traditional silicon-based germanium photoelectric detector drops sharply from 1.55μm, resulting in the low response rate of the traditional silicon-based germanium avalanche detector in the low transmission loss optical band, thereby improving the sensitivity, high-band response rate and detection performance level of the photoelectric detector. In addition, the stress source layer is used as an anti-reflection layer at the same time, which can achieve effective absorption of the incident light and reduce reflection loss. In addition, due to the introduction of the stress source layer, the light absorption layer (intrinsic germanium layer) film can be reduced in thickness under the influence of tensile strain without affecting the absorption coefficient, thereby reducing the carrier transport time and increasing the 3dB bandwidth, thereby further improving the performance of the device. BRIEF DESCRIPTION OF THE DRAWINGS
[0017] Figure 1 The figure is a schematic structural diagram of a photoelectric detection device according to a preferred embodiment of the utility model. DETAILED DESCRIPTION
[0018] In order to make the purpose, technical scheme and advantages of the embodiments of the utility model clearer, the technical scheme in the embodiments of the utility model will be clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the utility model. Unless otherwise defined, the technical terms or scientific terms used herein should be understood by people with general skills in the field to which the utility model belongs. "Including" and similar words used in this article mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects.
[0019] In order to solve the problem that the absorption coefficient of traditional silicon-based germanium photodetectors drops sharply from 1.55μm, resulting in low response rate of traditional silicon-based germanium photodetectors between low transmission loss optical bands, the utility model provides a high response rate photodetector device that can be used for light detection between low transmission loss optical bands.
[0020] The utility model provides a photoelectric detection device, comprising:
[0021] A photoelectric detection device layer is arranged on a substrate, and a stress source layer is coated on the photoelectric detection device layer, the photoelectric detection device layer is provided with a light absorption region layer, and the stress source layer is used to provide stress to the light absorption region layer, so that the light absorption region layer generates corresponding tensile strain, so that the light absorption region layer changes from an indirect band gap structure to a direct band gap structure, thereby increasing the absorption coefficient in the response band of the light absorption region layer, and the response wavelength can also be extended accordingly.
[0022] Therefore, the utility model can solve the problem that the absorption coefficient of traditional silicon-based germanium photodetectors drops sharply from 1.55μm, resulting in low response rate of traditional silicon-based germanium avalanche detectors in low transmission loss optical bands, thereby improving the sensitivity, high-band response rate and detection performance level of photodetectors.
[0023] The specific implementation of the utility model is further described in detail below in conjunction with the accompanying drawings.
[0024] refer to Figure 1 The photoelectric detection device of the present invention includes a photoelectric detection device layer 200 disposed on a substrate, and a stress source layer 16 coated on the photoelectric detection device layer 200 .
[0025] Among them, a light absorption region layer 14 is provided on the top of the photodetection device layer 200, and the stress source layer 16 is coated on the light absorption region layer 14. Therefore, based on the stress generated by itself, the stress source layer 16 can transfer stress to the light absorption region layer 14, so that the light absorption region layer 14 can obtain a higher tensile strain accordingly, thereby transforming the light absorption region layer 14 from having an indirect band gap structure to a direct band gap structure.
[0026] In some embodiments, an anti-reflection layer is further coated on the photodetection device layer 200. In addition, the stressor layer 16 also serves as the anti-reflection layer.
[0027] refer to Figure 1 In some embodiments, a first substrate layer 13 is provided on the substrate. The photodetection device layer 200 includes a first contact region 20 of a first conductivity type sequentially provided on the surface of the first substrate layer 13, a multiplication region layer 19 provided on the first contact region 20, a second contact region 18 of a second conductivity type provided on the surface of the multiplication region layer 19, a light absorption region layer 14 provided on the second contact region 18, and a third contact region 15 of a second conductivity type provided on the surface of the light absorption region layer 14. The stressor layer 16 is coated on the surface and side of the light absorption region layer 14 including the third contact region 15 and on the side of the multiplication region layer 19 including the second contact region 18.
[0028] In some embodiments, the first substrate layer 13 may be, for example, a first silicon substrate layer 131. The multiplication region layer 19 may be, for example, an intrinsic silicon layer 191. The light absorption region layer 14 may be, for example, an intrinsic germanium layer 141.
[0029] The first conductivity type is one of the N type and the P type, and the second conductivity type is the other of the N type and the P type.
[0030] refer to Figure 1 . In some embodiments, the first contact region 20 includes an N-type first doping region 201, the second contact region 18 includes a P-type second doping region 181, and the third contact region 15 includes a P-type third doping region 151. In this embodiment, the first contact region 20 is an N-type heavily doped first doping region 201 formed by heavily doping the upper surface of the active region on the first silicon substrate layer 131 with N-type (the figure shows the region of the first silicon substrate layer 131 located in the active region); the second contact region 18 is a P-type heavily doped second doping region 181 formed by heavily doping the upper surface of the intrinsic silicon layer 191 with P-type, and the third contact region 15 is a P-type heavily doped third doping region 151 formed by heavily doping the upper surface of the intrinsic germanium layer 141 with P-type.
[0031] In some other embodiments, the first contact region includes a P-type first doping region, the second contact region includes an N-type second doping region, and the third contact region includes an N-type third doping region.
[0032] refer to Figure 1 In some embodiments, the stressor layer 16 also covers the surface of the first contact region 20 (ie, the upper surface of the first silicon substrate layer 131 ).
[0033] Furthermore, it also includes: a plurality of contact electrodes 17. Each contact electrode 17 passes through the stressor layer 16 from above and is correspondingly connected to the surface of the first contact region 20 other than the side of the multiplication region layer 19 and the surface of the third contact region 15 (ie, the upper surface of the intrinsic germanium layer 141).
[0034] In some embodiments, the stressor layer 16 includes a silicon nitride layer 161. As the stressor layer 16, the silicon nitride layer 161 has the dual advantages of compatibility with CMOS processes and flexible control of stress transfer to obtain high tensile strain of germanium. The silicon nitride layer 161 also acts as an anti-reflection layer, which can reduce reflection loss and achieve effective absorption of incident light.
[0035] The principle of the utility model is that direct bandgap semiconductors are expected to show efficient radiative recombination and may obtain optical gain with a reasonable injected carrier density. Germanium is an indirect bandgap semiconductor. The transition from an indirect bandgap to a direct bandgap structure can be achieved by applying tensile strain, because the energy positions of different bandgaps change with the change of strain in the layer. When tensile strain is introduced, the introduction of tensile strain will lead to a reduction in the Γ valley and L valley of the germanium conduction band of the light absorption layer, and at the same time, the separation of the light hole and heavy hole valence bands of germanium will make the bandgap of germanium smaller, and it will change from an indirect bandgap semiconductor to a direct bandgap semiconductor. Moreover, as the bandgap of strained germanium is reduced, the absorption coefficient in its response band increases, and the response wavelength of the germanium film can also be extended accordingly.
[0036] In some embodiments, the contact electrode 17 includes an aluminum electrode 171 , but is not limited thereto.
[0037] In some embodiments, the sidewalls of the light absorption region layer 14 are aligned with the sidewalls of the multiplication region layer 19 .
[0038] Above Figure 1 The photoelectric detection device in the embodiment forms a silicon-based germanium avalanche detector (device) coated with a multiplex film layer of a stress source layer 16 and an anti-reflection layer.
[0039] refer to Figure 1 In some embodiments, a dielectric isolation layer 12 and a second substrate layer 11 are further provided on the substrate. The dielectric isolation layer 12 is provided on the surface of the first silicon substrate layer 131 facing away from the first contact region 20, and the second substrate layer 11 is provided on the surface of the dielectric isolation layer 12 facing away from the first silicon substrate layer 131.
[0040] In some embodiments, the second substrate layer 11 may be, for example, a second silicon substrate layer 111. The dielectric isolation layer 12 may be, for example, a silicon dioxide layer 121.
[0041] In some embodiments, the substrate may be, for example, an SOI substrate 100; the SOI substrate 100 is provided with a bottom silicon layer 101, a buried oxide layer 102, and a top silicon layer 103 in sequence. The top silicon layer 103 is a first silicon substrate layer 131, the bottom silicon layer 101 is a second silicon substrate layer 111, and the buried oxide layer 102 is a silicon dioxide layer 121.
[0042] The silicon-based germanium avalanche photodetector device of the present invention can be made by bonding a SOI substrate 100 with a germanium material. In some embodiments, first, a layer of N-type heavily doped first contact region 20 is formed on the active region surface of the top silicon layer 103 of the SOI substrate 100 by ion implantation, serving as the cathode of the multiplication region layer 19.
[0043] Subsequently, an intrinsic silicon layer 191 is formed on the first contact region 20 by an epitaxial method as the multiplication region layer 19 .
[0044] Then, by an ion implantation method, a layer of P-type heavily doped second contact region 18 is implanted on the upper surface of the intrinsic silicon layer 191 to serve as an anode of the multiplication region layer 19 .
[0045] The germanium light absorption region layer 14 is prepared by epitaxy. In the determined second contact region 18, a germanium material is grown by a high-low temperature two-step method to prepare the germanium light absorption region layer 14. And the excess germanium film is removed by thinning technology. Then, a P-type heavily doped third contact region 15 is formed on the top of the germanium light absorption region layer 14 by ion implantation, which serves as the contact layer of the germanium light absorption region layer 14 of the detector.
[0046] The silicon nitride stressor layer 16 is prepared on the prepared silicon-based germanium avalanche detection device, and the excess film is removed by chemical mechanical polishing to make the device surface flat.
[0047] Subsequently, the silicon nitride layer 161 is subjected to photolithography and etching to form a groove serving as the contact electrode 17 .
[0048] Finally, aluminum electrodes 171 are formed in the grooves by, for example, physical vapor deposition.
[0049] In summary, the utility model improves the traditional silicon-based germanium photodetector according to the requirements of the test band, takes advantage of the high tensile strain of germanium by utilizing the compatibility of silicon nitride with the CMOS process and the flexible control of stress transfer, introduces silicon nitride as the stress source layer 16, and transforms the germanium light absorption region layer 14 from an indirect bandgap structure to a direct bandgap structure, thereby increasing the absorption coefficient in the response band of the germanium light absorption region layer 14, and the response wavelength can also be extended accordingly. Therefore, it can solve the problem that the absorption coefficient of the traditional silicon-based germanium photodetector drops sharply from 1.55μm, resulting in the low response rate of the traditional silicon-based germanium avalanche detector in the low transmission loss optical band, thereby improving the sensitivity, high-band response rate and detection performance level of the photodetector.
[0050] At the same time, the silicon nitride layer 161 is used to cover the entire device and also serves as an anti-reflection layer, which can effectively absorb the incident light and reduce reflection loss.
[0051] Moreover, due to the introduction of the silicon nitride stress source layer 16, the germanium film in the light absorption region layer 14 can be reduced in thickness under the influence of tensile strain without affecting the absorption coefficient, thereby reducing the carrier transport time and increasing the 3dB bandwidth, thereby further improving the performance of the device.
[0052] The above advantages make the utility model have good application prospects.
[0053] Although the embodiments of the present invention are described in detail above, it is obvious to those skilled in the art that various modifications and variations can be made to these embodiments. However, it should be understood that such modifications and variations are within the scope and spirit of the present invention as described in the claims. Moreover, the present invention described herein may have other embodiments and may be implemented or realized in a variety of ways.
Claims
1. A photoelectric detection device, characterized in that: include: A photodetection device layer disposed on a substrate, and a stressor layer coated on the photodetection device layer, wherein the photodetection device layer is provided with a light absorption region layer, and the stressor layer is used to provide stress to the light absorption region layer so that the light absorption region layer generates a tensile strain correspondingly, so that the light absorption region layer changes from an indirect band gap structure to a direct band gap structure; The substrate is an SOI substrate, the light absorption region layer is grown by a high-low temperature two-step method using germanium material, and the thickness of the germanium light absorption region layer is reduced by thinning.
2. The photoelectric detection device according to claim 1, characterized in that: The photoelectric detection device layer is also coated with an anti-reflection layer, and the stress source layer also serves as the anti-reflection layer.
3. The photoelectric detection device according to claim 2, characterized in that: The photoelectric detection device includes a silicon-based germanium avalanche detector coated with the stressor layer.
4. The photoelectric detection device according to claim 1, characterized in that: A first substrate layer is provided on the substrate, and the photodetection device layer includes a first contact area of a first conductivity type provided in sequence on the surface of the first substrate layer, a multiplication area layer provided on the first contact area, a second contact area of a second conductivity type provided on the surface of the multiplication area layer, the light absorption area layer provided on the second contact area, and a third contact area of a second conductivity type provided on the surface of the light absorption area layer, and the stress source layer is coated on the surface and side surfaces of the light absorption area layer including the third contact area and on the side surfaces of the multiplication area layer including the second contact area.
5. The photoelectric detection device according to claim 4, characterized in that: The stressor layer also covers the surface of the first contact region.
6. The photoelectric detection device according to claim 4, characterized in that: The first conductivity type is one of N-type and P-type, and the second conductivity type is the other of N-type and P-type.
7. The photoelectric detection device according to claim 6, characterized in that: The first contact region includes an N-type first doping region, the second contact region includes a P-type second doping region, and the third contact region includes a P-type third doping region.
8. The photoelectric detection device according to claim 6, characterized in that: The first contact region includes a P-type first doping region, the second contact region includes an N-type second doping region, and the third contact region includes an N-type third doping region.
9. The photoelectric detection device according to claim 5, characterized in that: Also includes: A plurality of contact electrodes are provided, each of the contact electrodes passes through the stressor layer and is correspondingly connected to the first contact region and the third contact region outside the side surface of the multiplication region layer.
10. The photoelectric detection device according to claim 4, characterized in that: A dielectric isolation layer and a second substrate layer are also provided on the substrate. The dielectric isolation layer is provided on a surface of the first substrate layer facing away from the first contact area, and the second substrate layer is provided on a surface of the dielectric isolation layer facing away from the first substrate layer.