Photodetector and manufacturing method therefor
By forming doped regions and semiconductor layers with opposite doping types on SOI substrates, and combining epitaxial processes with metal silicide layers, the problem of germanium absorption layer damage during etching is solved, thereby improving the performance and efficiency of photodetectors.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- WUHAN XINXIN SEMICON MFG CO LTD
- Filing Date
- 2025-12-03
- Publication Date
- 2026-06-18
Smart Images
Figure CN2025139550_18062026_PF_FP_ABST
Abstract
Description
Photodetector and its manufacturing method Technical Field
[0001] This invention relates to the field of semiconductors, and in particular to a photodetector and its manufacturing method. Background Technology
[0002] In silicon-based photonics technology, photodetectors are used to convert optical signals into electrical signals. They typically come in two types: horizontal pin junctions and vertical pin junctions. Vertical pin junction photodetectors are favored due to their higher response bandwidth. However, vertical pin junction photodetectors have the following problems:
[0003] During the fabrication of contact plugs on the germanium absorber layer, over-etching can occur when etching to form the contact holes corresponding to the contact plugs, resulting in damage to the surface of the germanium absorber layer and introducing defects.
[0004] Therefore, improving the manufacturing process of photodetectors to avoid affecting their performance is an urgent problem to be solved. Summary of the Invention
[0005] The purpose of this invention is to provide a photodetector and its manufacturing method, which enables the avoidance of affecting the performance of the photodetector.
[0006] To achieve the above objectives, the present invention provides a method for manufacturing a photodetector, comprising:
[0007] An SOI substrate is provided, the SOI substrate comprising, from bottom to top, a lower substrate, an insulating buried layer and a semiconductor layer;
[0008] Doped regions are formed in the semiconductor layer;
[0009] A semiconductor absorber layer is formed on a portion of the doped region;
[0010] A semiconductor doped layer is formed on the semiconductor absorber layer, wherein the doping type of the doped region is opposite to that of the semiconductor doped layer.
[0011] Optionally, the method for manufacturing the photodetector further includes:
[0012] A groove is formed in the semiconductor layer, and the groove is located in the doped region surrounding the semiconductor absorption layer.
[0013] Optionally, the groove is spaced apart from the semiconductor absorption layer.
[0014] Optionally, the step of forming the semiconductor doped layer on the semiconductor absorber layer includes:
[0015] An epitaxial process is performed to form a semiconductor material layer on the semiconductor absorber layer, and the semiconductor material layer is doped.
[0016] Optionally, the method for manufacturing the photodetector further includes:
[0017] A metal silicide layer is formed on top of the semiconductor doped layer and / or on top of the doped regions on both sides of the semiconductor absorber layer.
[0018] Optionally, the method for manufacturing the photodetector further includes:
[0019] A first electrode and a second electrode are formed on the semiconductor doped layer and the doped region, respectively.
[0020] Optionally, the doped region is formed in the semiconductor layer of part or all of its thickness.
[0021] Optionally, the semiconductor absorber layer is made of a different material than the semiconductor layer.
[0022] Optionally, the step of forming the semiconductor absorber layer on a portion of the doped region includes: forming an insulating dielectric layer on the doped region; etching the insulating dielectric layer to form an opening exposing a portion of the surface of the doped region; and performing an epitaxial process to form the semiconductor absorber layer on the exposed doped region.
[0023] The present invention also provides a photodetector, comprising:
[0024] SOI substrate, including, from bottom to top, a lower substrate, an insulating buried layer and a semiconductor layer;
[0025] Doped regions are formed in the semiconductor layer;
[0026] A semiconductor absorber layer is formed on a portion of the doped region;
[0027] A semiconductor doped layer is formed on the semiconductor absorber layer, wherein the doping type of the doped region is opposite to that of the semiconductor doped layer.
[0028] Optionally, a groove is formed in the doped region surrounding the semiconductor absorber layer, and the groove is covered by an insulating dielectric layer.
[0029] Optionally, the groove is spaced apart from the semiconductor absorption layer.
[0030] Optionally, the photodetector further includes:
[0031] A metal silicide layer is formed on top of the semiconductor doped layer and / or on top of the doped regions on both sides of the semiconductor absorber layer.
[0032] Optionally, the photodetector further includes:
[0033] The first electrode and the second electrode are electrically connected to the semiconductor doped layer and the doped region, respectively.
[0034] Optionally, the second electrode, which is electrically connected to the doped region, is formed on at least one side of the semiconductor absorber layer.
[0035] Optionally, the groove is a continuous ring, and the groove surrounds the semiconductor absorption layer.
[0036] Optionally, the semiconductor absorber layer is made of germanium, indium gallium arsenide, or indium gallium arsenide phosphide; or, the semiconductor absorber layer is made of silicon, germanium arsenide, or indium phosphide.
[0037] Optionally, the material of the semiconductor doped layer includes silicon.
[0038] Optionally, the metal component in the metal silicide layer includes at least one of titanium, cobalt, and nickel.
[0039] Optionally, the semiconductor absorber layer is undoped, and the doping type of the semiconductor doped layer is opposite to that of the doped region.
[0040] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:
[0041] 1. The method for manufacturing a photodetector according to the present invention includes: providing an SOI substrate, the SOI substrate comprising, from bottom to top, a lower substrate, an insulating buried layer, and a semiconductor layer; forming a doped region in the semiconductor layer; forming a semiconductor absorber layer on a portion of the doped region; and forming a semiconductor doped layer on the semiconductor absorber layer, wherein the doping type of the doped region is opposite to that of the semiconductor doped layer. This enables the avoidance of affecting the performance of the photodetector.
[0042] 2. The photodetector of the present invention comprises: an SOI substrate, including a lower substrate, an insulating buried layer, and a semiconductor layer from bottom to top; a doped region formed in the semiconductor layer; a semiconductor absorption layer formed on a portion of the doped region; and a semiconductor doped layer formed on the semiconductor absorption layer, wherein the doping type of the doped region is opposite to that of the semiconductor doped layer. This enables the avoidance of affecting the performance of the photodetector. Attached Figure Description
[0043] Figure 1 is a flowchart of a method for manufacturing a photodetector according to an embodiment of the present invention;
[0044] Figures 2a to 2h are schematic diagrams of the devices used in the manufacturing method of the photodetector shown in Figure 1.
[0045] The reference numerals in Figures 1 to 2h are explained as follows:
[0046] 101-Lower substrate; 102-Buried insulating layer; 103-Semiconductor layer; 104-Groove; 11-Doped region; 12-Semiconductor absorber layer; 13-Semiconductor doped layer; 14-First insulating dielectric layer; 141-First opening; 15-Second insulating dielectric layer; 151-Second opening; 152-Third opening; 16-Metal silicide layer; 17-Third insulating dielectric layer; 18-Conductive structure. Detailed Implementation
[0047] To make the objectives, advantages, and features of the present invention clearer, the photodetector and its manufacturing method proposed in this invention will be further described in detail below with reference to the accompanying drawings. It should be noted that the drawings are all in a very simplified form and use non-precise proportions, and are only used to facilitate and clarify the illustration of the embodiments of the present invention.
[0048] An embodiment of the present invention provides a method for manufacturing a photodetector. Referring to FIG1, FIG1 is a flowchart of a method for manufacturing a photodetector according to an embodiment of the present invention. The method for manufacturing a photodetector includes:
[0049] Step S1: Provide an SOI (Semiconductor-On-Insulator) substrate, wherein the SOI substrate comprises, from bottom to top, a lower substrate, an insulating buried layer, and a semiconductor layer;
[0050] Step S2: Form a doped region in the semiconductor layer;
[0051] Step S3: Form a semiconductor absorber layer on a portion of the doped region;
[0052] Step S4: Form a semiconductor doped layer on the semiconductor absorber layer, wherein the doping type of the doped region is opposite to that of the semiconductor doped layer.
[0053] The manufacturing method of the photodetector provided in this embodiment is described in more detail below with reference to Figures 2a to 2h.
[0054] According to step S1, referring to FIG2a, an SOI substrate is provided, the SOI substrate comprising a lower substrate 101, an insulating buried layer 102 and a semiconductor layer 103 from bottom to top.
[0055] The semiconductor layer 103 can be made of semiconductor materials such as silicon.
[0056] According to step S2, referring to FIG2b, a doped region 11 is formed in the semiconductor layer 103.
[0057] The doped region 11 may be formed in the semiconductor layer 103, which has a partial or full thickness (as shown in FIG2b).
[0058] According to step S3, referring to FIG2d, a semiconductor absorption layer 12 is formed on a portion of the doped region 11.
[0059] Preferably, the semiconductor absorber layer 12 is made of Ge (germanium), InGaAs (indium gallium arsenide), or InGaAsP (indium gallium arsenide phosphide); in other embodiments, the semiconductor absorber layer 12 may be made of Si (silicon), GeAs (germanium arsenide), or InP (indium phosphide).
[0060] In one embodiment, the step of forming the semiconductor absorber layer 12 on a portion of the doped region 11 includes: first, as shown in FIG2c, forming a first insulating dielectric layer 14 on the doped region 11; then, etching the first insulating dielectric layer 14 to form a first opening 141 exposing a portion of the surface of the doped region 11; and then, as shown in FIG2d, performing an epitaxial process to form the semiconductor absorber layer 12 on the exposed doped region 11.
[0061] In one embodiment, when the semiconductor absorber layer 12 and the semiconductor layer 103 are made of different materials (e.g., the semiconductor layer 103 is made of silicon and the semiconductor absorber layer 12 is made of germanium), the semiconductor absorber layer 12 formed on the semiconductor layer 103 is a heteroepitaxial layer. This means that the semiconductor absorber layer 12 will not grow along the same direction as the crystal orientation of the semiconductor layer 103. Instead, the semiconductor absorber layer 12 will grow along multiple directions with different crystal orientations, such as (110), (100), and (001). The growth rates on different crystal orientations are different, and sharp corners will be formed in the direction of the crystal orientation with a faster growth rate, resulting in an irregular polygonal shape (e.g., a hexagon in Figure 2d) in the longitudinal cross-section of the semiconductor absorber layer 12. Optionally, the semiconductor absorber layer 12 can also be shaped by processes such as etching.
[0062] In one embodiment, the semiconductor absorption layer 12 is undoped, that is, the semiconductor absorption layer 12 is in an intrinsic state.
[0063] In one embodiment, the method for manufacturing the photodetector further includes forming a groove 104 in the semiconductor layer 103, the groove 104 being located in the doped region 11 surrounding the semiconductor absorption layer 12. As shown in FIG2a, the groove 104 may be formed before the formation of the doped region 11; or, the groove 104 may be formed after the formation of the doped region 11 and before the formation of the first insulating dielectric layer 14. In other embodiments, the groove 104 may not be formed in the semiconductor layer 103.
[0064] The groove 104 may be located in the doped region 11 on one or both sides of the semiconductor absorption layer 12; or the groove 104 may be a continuous ring, surrounding the semiconductor absorption layer 12.
[0065] The groove 104 does not penetrate the doped region 11, and the first insulating dielectric layer 14 fills the groove 104.
[0066] In one embodiment, the groove 104 is spaced apart from the semiconductor absorber layer 12. As shown in FIG2c, when the first opening 141 is formed in the first insulating dielectric layer 14, the first opening 141 only exposes the top surface of the middle region of the doped region 11 between adjacent grooves 104, so as to prevent the subsequent formation of the semiconductor absorber layer 12 in the groove 104.
[0067] According to step S4, referring to FIG2e, a semiconductor doped layer 13 is formed on the semiconductor absorber layer 12, wherein the doping type of the doped region 11 is opposite to that of the semiconductor doped layer 13.
[0068] The semiconductor doped layer 13 can be made of semiconductor materials such as silicon.
[0069] When the doping type of the doped region 11 is P-type and the doping type of the semiconductor doped layer 13 is N-type, the doped region 11, the semiconductor absorber layer 12, and the semiconductor doped layer 13 form a vertical PIN junction; when the doping type of the doped region 11 is N-type and the doping type of the semiconductor doped layer 13 is P-type, the doped region 11, the semiconductor absorber layer 12, and the semiconductor doped layer 13 form a vertical NIP junction.
[0070] In one embodiment, the step of forming the semiconductor doped layer 13 on the semiconductor absorber layer 12 includes: performing an epitaxial process to form a semiconductor material layer on the semiconductor absorber layer 12, and doping the semiconductor material layer. In one embodiment, an in-situ doping process can be used, that is, a gas such as silane can be introduced into the reaction chamber, and a gas containing the required dopant ions can be introduced into the reaction chamber according to the doping type of the semiconductor doped layer 13.
[0071] When in-situ doping is used, since the semiconductor doping layer 13 is not doped by ion implantation, damage to the semiconductor absorption layer 12 and the introduction of defects can be avoided, thereby avoiding affecting the performance of the photodetector.
[0072] In one embodiment, the method for manufacturing the photodetector further includes: as shown in FIG2g, forming a metal silicide layer 16 on top of the semiconductor doped layer 13 and / or on top of the doped regions 11 on both sides of the semiconductor absorber layer 12.
[0073] The steps may include: as shown in FIG2f, forming a second insulating dielectric layer 15 covering the semiconductor doped layer 13, the second insulating dielectric layer 15 filling the first opening 141, and the second insulating dielectric layer 15 extending to the first insulating dielectric layer 14; then, as shown in FIG2g, etching the second insulating dielectric layer 15 to form a second opening 151 exposing the top surface of the semiconductor doped layer 13, and etching the second insulating dielectric layer 15 and the first insulating dielectric layer 14 to form a third opening 152 exposing the top surface of the doped region 11 portions on both sides of the semiconductor absorber layer 12; then, forming a metal silicide layer 16 on the exposed top of the semiconductor doped layer 13 and the exposed top of the doped region 11.
[0074] The metal in the metal silicide layer 16 can be at least one of Ti (titanium), Co (cobalt), and Ni (nickel).
[0075] As shown in Figure 2h, the manufacturing method of the photodetector further includes: forming conductive structures 18 on the semiconductor doped layer 13 and the doped region 11 respectively, wherein the conductive structures 18 are electrically connected to the semiconductor doped layer 13 or the doped region 11 respectively.
[0076] The steps may include: filling the third insulating dielectric layer 17 into the second opening 151 and the third opening 152; then etching the third insulating dielectric layer 17 to form a contact hole exposing the metal silicide layer 16; then filling the contact hole with a metal material, which also covers the third insulating dielectric layer 17 and the second insulating dielectric layer 15, and etching the metal material to form conductive structures 18 on the metal silicide layer 16 on top of the semiconductor doped layer 13 and on the metal silicide layer 16 on top of the doped region 11, respectively.
[0077] The conductive structure 18 includes a portion formed in the contact hole and portions extending to the periphery of the contact hole on the surfaces of the third insulating dielectric layer 17 and the second insulating dielectric layer 15.
[0078] In one embodiment, the portion of the conductive structure 18 located in the contact hole is made of W (tungsten), and the portion of the conductive structure 18 extending to the surfaces of the third insulating dielectric layer 17 and the second insulating dielectric layer 15 around the contact hole is made of Cu (copper).
[0079] The semiconductor doped layer 13 and the conductive structure 18 above the doped region 11 serve as the first electrode and the second electrode of the photodetector, respectively.
[0080] Since the semiconductor doped layer 13 and the doped region 11 are each formed with the conductive structure 18, the contact resistance between the semiconductor doped layer 13 and the doped region 11 and the conductive structure 18 can be reduced, thereby improving the performance of the photodetector.
[0081] The working principle of the photodetector includes: the semiconductor layer 103 acts as a waveguide, guiding incident light into the semiconductor absorption layer 12, where the semiconductor absorption layer 12 absorbs the incident light, thereby generating photogenerated carriers; the semiconductor doped layer 13 and the doped region 11 respectively form contact with the conductive structure 18 on it, collecting photogenerated carriers and forming a photocurrent.
[0082] In one embodiment, when the groove 104 is formed in the doped region 11 surrounding the semiconductor absorption layer 12, the light field can be concentrated directly below the semiconductor absorption layer 12, reducing light spillover and making it more conducive for the semiconductor absorption layer 12 to absorb incident light.
[0083] Preferably, the conductive structure 18 is formed above the doped regions 11 on both sides of the semiconductor absorption layer 12, thereby increasing the photocurrent collection path and improving the performance of the photodetector. In other embodiments, the conductive structure 18 may be formed above the doped region 11 on one side of the semiconductor absorption layer 12.
[0084] As can be seen from the above, by forming the semiconductor doped layer 13 on the semiconductor absorber layer 12, and with the doping type of the doped region 11 below the semiconductor absorber layer 12 being opposite to that of the semiconductor doped layer 13, it is possible to form a doped region on top of the semiconductor absorber layer 12 without using an ion implantation process. This allows for the formation of a PIN junction or NIP junction while avoiding damage to the semiconductor absorber layer 12 and the introduction of defects, thereby preventing any impact on the performance of the photodetector. Furthermore, by forming the semiconductor doped layer 13 on the semiconductor absorber layer 12, the subsequent fabrication of the conductive structure 18 is facilitated. During the etching process, even if over-etching occurs when forming the contact hole corresponding to the conductive structure 18, only the semiconductor doped layer 13 will be etched, and the semiconductor absorption layer 12 will not be etched. This avoids damage to the semiconductor absorption layer 12 and the introduction of defects, thereby avoiding affecting the performance of the photodetector. Furthermore, by forming the semiconductor doped layer 13 on the semiconductor absorption layer 12, the metal silicide layer 16 can be formed on the semiconductor doped layer 13 subsequently. This avoids direct contact between the semiconductor doped layer 13 and the conductive structure 18, which would result in a large contact resistance and thus avoid affecting the performance of the photodetector.
[0085] In summary, the method for manufacturing a photodetector provided by the present invention includes: providing an SOI substrate, the SOI substrate comprising, from bottom to top, a lower substrate, an insulating buried layer, and a semiconductor layer; forming a doped region in the semiconductor layer; forming a semiconductor absorber layer on a portion of the doped region; and forming a semiconductor doped layer on the semiconductor absorber layer, wherein the doping type of the doped region is opposite to that of the semiconductor doped layer. The method for manufacturing a photodetector of the present invention can avoid affecting the performance of the photodetector.
[0086] An embodiment of the present invention provides a photodetector, comprising: an SOI substrate, including a lower substrate, an insulating buried layer, and a semiconductor layer from bottom to top; a doped region formed in the semiconductor layer; a semiconductor absorption layer formed on a portion of the doped region; and a semiconductor doped layer formed on the semiconductor absorption layer, wherein the doping type of the doped region is opposite to that of the semiconductor doped layer.
[0087] The photodetector provided in this embodiment is described in more detail below with reference to Figure 2h.
[0088] The SOI substrate includes, from bottom to top, a lower substrate 101, an insulating buried layer 102, and a semiconductor layer 103.
[0089] The semiconductor layer 103 can be made of semiconductor materials such as silicon.
[0090] The doped region 11 is formed in the semiconductor layer 103.
[0091] The doped region 11 may be formed in the semiconductor layer 103, which has a partial or full thickness (as shown in FIG2h).
[0092] The semiconductor absorber layer 12 is formed on a portion of the doped region 11.
[0093] Preferably, the semiconductor absorber layer 12 is made of Ge (germanium), InGaAs (indium gallium arsenide), or InGaAsP (indium gallium arsenide phosphide); in other embodiments, the semiconductor absorber layer 12 may be made of Si (silicon), GeAs (germanium arsenide), or InP (indium phosphide).
[0094] In one embodiment, when the semiconductor absorber layer 12 and the semiconductor layer 103 are made of different materials (e.g., the semiconductor layer 103 is made of silicon and the semiconductor absorber layer 12 is made of germanium), the semiconductor absorber layer 12 is epitaxially grown on the semiconductor layer 103 as a heteroepitaxial growth. This causes the semiconductor absorber layer 12 to grow along a direction that is not the same as the crystal orientation of the semiconductor layer 103. Instead, the semiconductor absorber layer 12 grows along multiple directions with different crystal orientations, such as (110), (100), and (001). The growth rates on different crystal orientations are different, and sharp corners are formed in the direction of the crystal orientation with a faster growth rate, resulting in an irregular polygonal shape (e.g., a hexagon in Figure 2h) in the longitudinal cross-section of the semiconductor absorber layer 12. Optionally, the semiconductor absorber layer 12 can also be shaped by etching or other processes.
[0095] In one embodiment, the semiconductor absorption layer 12 is undoped, that is, the semiconductor absorption layer 12 is in an intrinsic state.
[0096] In one embodiment, a groove (i.e., groove 104 in FIG. 2a) is formed in the doped region 11 surrounding the semiconductor absorber layer 12, and the groove 104 is covered by an insulating dielectric layer. In other embodiments, the groove 104 may not be formed in the doped region 11.
[0097] The groove 104 may be located in the doped region 11 on one or both sides of the semiconductor absorption layer 12; or the groove 104 may be a continuous ring, surrounding the semiconductor absorption layer 12.
[0098] The groove 104 does not penetrate the doped region 11.
[0099] In one embodiment, the groove 104 is spaced apart from the semiconductor absorption layer 12 to prevent the semiconductor absorption layer 12 from being formed in the groove 104.
[0100] The semiconductor doped layer 13 is formed on the semiconductor absorber layer 12, and the doping type of the doped region 11 is opposite to that of the semiconductor doped layer 13.
[0101] The semiconductor doped layer 13 can be made of semiconductor materials such as silicon.
[0102] When the doping type of the doped region 11 is P-type and the doping type of the semiconductor doped layer 13 is N-type, the doped region 11, the semiconductor absorber layer 12, and the semiconductor doped layer 13 form a vertical PIN junction; when the doping type of the doped region 11 is N-type and the doping type of the semiconductor doped layer 13 is P-type, the doped region 11, the semiconductor absorber layer 12, and the semiconductor doped layer 13 form a vertical NIP junction.
[0103] In one embodiment, the photodetector further includes a metal silicide layer 16 formed on top of the semiconductor doped layer 13 and / or on top of the doped regions 11 on both sides of the semiconductor absorber layer 12.
[0104] The metal in the metal silicide layer 16 can be at least one of Ti (titanium), Co (cobalt), and Ni (nickel).
[0105] The photodetector further includes a conductive structure 18, which is electrically connected to the semiconductor doped layer 13 and the doped region 11, respectively.
[0106] The insulating dielectric layer is formed on the semiconductor layer 103, and the insulating dielectric layer covers the doped region 11, the semiconductor absorber layer 12, the semiconductor doped layer 13 and the metal silicide layer 16. The conductive structure 18 is formed in the insulating dielectric layer on the metal silicide layer 16 and extends to the top surface of the insulating dielectric layer.
[0107] The insulating dielectric layer has a contact hole that exposes the semiconductor doped layer 13 and the doped region 11. The conductive structure 18 includes a portion formed in the contact hole and a portion extending to the surface of the insulating dielectric layer around the contact hole.
[0108] In one embodiment, the portion of the conductive structure 18 located in the contact hole is made of W (tungsten), and the portion of the conductive structure 18 extending to the surface of the insulating dielectric layer surrounding the contact hole is made of Cu (copper).
[0109] The insulating dielectric layer may include a multilayer structure, such as a first insulating dielectric layer 14, a second insulating dielectric layer 15, and a third insulating dielectric layer 17.
[0110] The semiconductor doped layer 13 and the conductive structure 18 above the doped region 11 serve as the first electrode and the second electrode of the photodetector, respectively.
[0111] Since the semiconductor doped layer 13 and the doped region 11 are each formed with the conductive structure 18, the contact resistance between the semiconductor doped layer 13 and the doped region 11 and the conductive structure 18 can be reduced, thereby improving the performance of the photodetector.
[0112] The working principle of the photodetector includes: the semiconductor layer 103 acts as a waveguide, guiding incident light into the semiconductor absorption layer 12, where the semiconductor absorption layer 12 absorbs the incident light, thereby generating photogenerated carriers; the semiconductor doped layer 13 and the doped region 11 respectively form contact with the conductive structure 18 on it, collecting photogenerated carriers and forming a photocurrent.
[0113] In one embodiment, when the groove 104 is formed in the doped region 11 surrounding the semiconductor absorption layer 12, the light field can be concentrated directly below the semiconductor absorption layer 12, reducing light spillover and making it more conducive for the semiconductor absorption layer 12 to absorb incident light.
[0114] Preferably, the conductive structure 18 is formed above the doped regions 11 on both sides of the semiconductor absorption layer 12, thereby increasing the photocurrent collection path and improving the performance of the photodetector. In other embodiments, the conductive structure 18 may be formed above the doped region 11 on one side of the semiconductor absorption layer 12.
[0115] As can be seen from the above, since the semiconductor doped layer 13 is formed on the semiconductor absorber layer 12, and the doping type of the doped region 11 below the semiconductor absorber layer 12 is opposite to that of the semiconductor doped layer 13, it is not necessary to form a doped region on the top of the semiconductor absorber layer 12 through ion implantation. This allows for the formation of a PIN junction or NIP junction while avoiding damage to the semiconductor absorber layer 12 and the introduction of defects, thereby avoiding affecting the performance of the photodetector. Furthermore, since the semiconductor doped layer 13 is formed on the semiconductor absorber layer 12, the subsequent fabrication of the conductive structure 18... During the etching process, even if over-etching occurs when forming the contact hole corresponding to the conductive structure 18, only the semiconductor doped layer 13 will be etched, and the semiconductor absorption layer 12 will not be etched. This avoids damage to the semiconductor absorption layer 12 and the introduction of defects, thereby avoiding affecting the performance of the photodetector. Furthermore, since the semiconductor doped layer 13 is formed on the semiconductor absorption layer 12, the metal silicide layer 16 can be formed on the semiconductor doped layer 13 subsequently. This avoids direct contact between the semiconductor doped layer 13 and the conductive structure 18, which would result in a large contact resistance and thus avoid affecting the performance of the photodetector.
[0116] In summary, the photodetector provided by this invention includes: an SOI substrate, comprising a lower substrate, an insulating buried layer, and a semiconductor layer from bottom to top; a doped region formed in the semiconductor layer; a semiconductor absorber layer formed on a portion of the doped region; and a semiconductor doped layer formed on the semiconductor absorber layer, wherein the doping type of the doped region is opposite to that of the semiconductor doped layer. The photodetector of this invention can avoid affecting the performance of the photodetector.
[0117] The above description is merely a description of preferred embodiments of the present invention and is not intended to limit the scope of the present invention in any way. Any changes or modifications made by those skilled in the art based on the above disclosure shall fall within the protection scope of the claims.
Claims
1. A method for manufacturing a photodetector, characterized in that, include: An SOI substrate is provided, the SOI substrate comprising, from bottom to top, a lower substrate, an insulating buried layer and a semiconductor layer; Doped regions are formed in the semiconductor layer; A semiconductor absorber layer is formed on a portion of the doped region; A semiconductor doped layer is formed on the semiconductor absorber layer, wherein the doping type of the doped region is opposite to that of the semiconductor doped layer.
2. The method for manufacturing a photodetector as described in claim 1, characterized in that, The method for manufacturing the photodetector further includes: A groove is formed in the semiconductor layer, and the groove is located in the doped region surrounding the semiconductor absorption layer.
3. The method for manufacturing a photodetector as described in claim 2, characterized in that, The groove is spaced apart from the semiconductor absorption layer.
4. The method for manufacturing a photodetector as described in claim 1, characterized in that, The step of forming the semiconductor doped layer on the semiconductor absorber layer includes: An epitaxial process is performed to form a semiconductor material layer on the semiconductor absorber layer, and the semiconductor material layer is doped.
5. The method for manufacturing a photodetector as described in claim 1, characterized in that, The method for manufacturing the photodetector further includes: A metal silicide layer is formed on top of the semiconductor doped layer and / or on top of the doped regions on both sides of the semiconductor absorber layer.
6. The method for manufacturing a photodetector as described in claim 1, characterized in that, The method for manufacturing the photodetector further includes: A first electrode and a second electrode are formed on the semiconductor doped layer and the doped region, respectively.
7. The method for manufacturing a photodetector as described in claim 1, characterized in that, The doped region is formed in the semiconductor layer, which has a partial or full thickness.
8. The method for manufacturing a photodetector as described in claim 1, characterized in that, The semiconductor absorber layer is made of a different material than the semiconductor layer.
9. The method for manufacturing a photodetector as described in claim 1, characterized in that, The step of forming the semiconductor absorber layer on a portion of the doped region includes: An insulating dielectric layer is formed on the doped region; The insulating dielectric layer is etched to form an opening that exposes a portion of the surface of the doped region; An epitaxial process is performed to form the semiconductor absorber layer on the exposed doped region.
10. A photodetector, characterized in that, include: SOI substrate, including, from bottom to top, a lower substrate, an insulating buried layer and a semiconductor layer; Doped regions are formed in the semiconductor layer; A semiconductor absorber layer is formed on a portion of the doped region; A semiconductor doped layer is formed on the semiconductor absorber layer, wherein the doping type of the doped region is opposite to that of the semiconductor doped layer.
11. The photodetector as claimed in claim 10, characterized in that, A groove is formed in the doped region surrounding the semiconductor absorber layer, and the groove is covered by an insulating dielectric layer.
12. The photodetector as claimed in claim 11, characterized in that, The groove is spaced apart from the semiconductor absorption layer.
13. The photodetector as described in claim 10, characterized in that, The photodetector also includes: A metal silicide layer is formed on top of the semiconductor doped layer and / or on top of the doped regions on both sides of the semiconductor absorber layer.
14. The photodetector as claimed in claim 10, characterized in that, The photodetector also includes: The first electrode and the second electrode are electrically connected to the semiconductor doped layer and the doped region, respectively.
15. The photodetector as claimed in claim 14, characterized in that, The second electrode, which is electrically connected to the doped region, is formed on at least one side of the semiconductor absorber layer.
16. The photodetector as claimed in claim 11, characterized in that, The groove is a continuous ring shape, surrounding and enclosing the semiconductor absorption layer.
17. The photodetector as claimed in claim 10, characterized in that, The semiconductor absorber layer is made of germanium, indium gallium arsenide, or indium gallium arsenide phosphide; or... The semiconductor absorber layer is made of silicon, germanium arsenide, or indium phosphide.
18. The photodetector as claimed in claim 10, characterized in that, The material of the semiconductor doped layer includes silicon.
19. The photodetector as claimed in claim 10, characterized in that, The metal composition in the metal silicide layer includes at least one of titanium, cobalt, and nickel.
20. The photodetector as claimed in claim 10, characterized in that, The semiconductor absorber layer is undoped, and the doping type of the semiconductor doped layer is opposite to that of the doped region.