A photodetector and a method of manufacturing the same

Abstract

The application provides an optoelectronic detector and a manufacturing method thereof. A multilayer optoelectronic detection film layer is formed on a target substrate. The optoelectronic detection film layer comprises a first film layer of a first type of doping, a second film layer and a third film layer of a second type of doping which are stacked in sequence. One of the first type of doping and the second type of doping is P-type doping, and the other is N-type doping. That is, the first film layer of the first type of doping, the second film layer and the third film layer of the second type of doping constitute an optoelectronic detection film layer based on a silicon germanium / silicon heterojunction, that is, an optoelectronic detection unit, which can realize photoelectric conversion. The multilayer optoelectronic detection film layer is repeatedly overlapped, that is, the vertical series connection of multiple optoelectronic detection units, which can directly improve the photoelectric conversion efficiency of the optoelectronic detector. In addition, different numbers of optoelectronic detection film layers can correspond to different photovoltaic electromotive forces, thereby meeting the regulation and control requirements of the photovoltaic electromotive force of the optoelectronic detector.

Description

Technical Field

[0001] This invention relates to the field of semiconductors, and in particular to a photodetector and its manufacturing method. Background Technology

[0002] With the development of semiconductor-related technologies, semiconductor devices are widely used in various fields. For example, photodetectors can convert light signals into electrical signals and can be used in fields such as detection or imaging.

[0003] There is currently a need to control the photogenerated electromotive force (EMF) of photodetectors to meet various application scenarios. However, most current methods for controlling the photogenerated EMF rely on complex material improvements and doping processes for photodetectors. Furthermore, the doping process results in photodetectors with low voltage and low photoelectric conversion efficiency. Summary of the Invention

[0004] In view of this, the purpose of this application is to provide a photodetector and a method for manufacturing the same, which can meet the requirements for controlling the photogenerated electromotive force of the photodetector and improve the photoelectric conversion efficiency.

[0005] This application provides a photodetector, the photodetector comprising:

[0006] Multiple photodetector films are formed on the target substrate;

[0007] The photodetector film layer includes a first film layer, a second film layer, and a third film layer doped with a first type of doping, which are stacked sequentially.

[0008] One of the first type of doping and the second type of doping is P-type doping and the other is N-type doping. The material of the second film layer is silicon-germanium, and the materials of the first film layer and the third film layer include at least silicon.

[0009] Optionally, the first film layer of the first type of doping is P-type doped silicon, and the second film layer of the second type of doping is N-type doped silicon.

[0010] Optionally, the photogenerated electromotive force of the photodetector is positively correlated with the number of layers in the photodetector film.

[0011] Optionally, the number of layers in the photodetector film is less than or equal to 100.

[0012] Optionally, the concentration of germanium in the second film layer ranges from 0.1 to 0.99.

[0013] This application provides a method for manufacturing a photodetector, the method comprising:

[0014] Multiple photodetector films are sequentially formed on the target substrate;

[0015] The photodetector film layer includes a first film layer, a second film layer, and a third film layer doped with a first type of doping, which are stacked sequentially.

[0016] One of the first type of doping and the second type of doping is P-type doping and the other is N-type doping. The material of the second film layer is silicon-germanium, and the materials of the first film layer and the second film layer include at least silicon.

[0017] Optionally, the step of sequentially forming multiple photodetector films on the target substrate includes:

[0018] Multilayer photodetector films are sequentially formed on the target substrate using depressurized chemical vapor deposition.

[0019] Optionally, the multilayer photodetector film includes a first photodetector film, the first photodetector film including a first sub-film layer doped with a first type, and the sequential formation of the multilayer photodetector film on the target substrate includes:

[0020] The first sub-film layer is formed on the target substrate using a doping process, and multiple photodetector films are sequentially formed on the first sub-film layer using depressurized chemical vapor deposition.

[0021] Optionally, the photogenerated electromotive force of the photodetector is positively correlated with the number of layers in the photodetector film.

[0022] Optionally, the number of layers in the photodetector film is less than or equal to 100.

[0023] This application provides a photodetector, which includes: a multilayer photodetector film formed on a target substrate. The photodetector film includes a first film layer, a second film layer, and a third film layer doped with a first type of doping, stacked sequentially. One of the first type of doping and the second type of doping is P-type doped and the other is N-type doped. The material of the second film layer is silicon-germanium, and the materials of the first film layer and the second film layer include at least silicon. That is, the first film layer, the second film layer, and the third film layer doped with the first type of doping constitute a photodetector film based on a silicon-germanium / silicon heterojunction, which constitutes a photodetector unit capable of photoelectric conversion. The repeated overlapping of the multilayer photodetector film layers, i.e., the vertical series connection of multiple photodetector units, can directly improve the photoelectric conversion efficiency of the photodetector. Furthermore, different numbers of photodetector film layers can correspond to different photogenerated electromotive forces, realizing the need to control the photogenerated electromotive force of the photodetector. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 A schematic diagram of the structure of a photodetector provided in an embodiment of this application is shown;

[0026] Figure 2 A schematic diagram of another photodetector provided in an embodiment of this application is shown;

[0027] Figure 3 A schematic flowchart of a method for manufacturing a photodetector according to an embodiment of this application is shown;

[0028] Figures 4-5 A schematic diagram of a photodetector manufactured according to the manufacturing method provided in the embodiments of this application is shown. Detailed Implementation

[0029] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present application.

[0030] Many specific details are set forth in the following description in order to provide a full understanding of this application. However, this application may also be implemented in other ways different from those described herein. Those skilled in the art can make similar extensions without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0031] This application is described in detail with reference to the schematic diagrams. When detailing the embodiments of this application, for ease of explanation, the cross-sectional views illustrating the device structure may be partially enlarged, not according to the usual scale. Furthermore, the schematic diagrams are merely examples and should not limit the scope of protection of this application. In actual fabrication, the three-dimensional spatial dimensions of length, width, and depth should be included.

[0032] With the development of semiconductor-related technologies, semiconductor devices are widely used in various fields. For example, photodetectors can convert light signals into electrical signals and can be used in fields such as detection or imaging.

[0033] There is currently a need to control the photogenerated electromotive force (EMF) of photodetectors to meet various application scenarios. However, most current methods for controlling the photogenerated EMF rely on complex doping processes on the photodetectors, which result in low voltage and low photoelectric conversion efficiency in the photodetectors manufactured using these processes.

[0034] Based on this, this application provides a photodetector, which includes: a multilayer photodetector film formed on a target substrate, the photodetector film including a first film layer, a second film layer and a third film layer doped with a first type of doping, stacked sequentially, one of the first type of doping and the other of the second type of doping being P-type doped and the other being N-type doped, the material of the second film layer being silicon-germanium, and the materials of the first film layer and the second film layer including at least silicon. That is, the first film layer, the second film layer and the third film layer doped with the first type of doping constitute a photodetector film based on a silicon-germanium / silicon heterojunction, that is, constitute a photodetector unit, which can realize photoelectric conversion. The repeated overlapping of the multilayer photodetector film layers, that is, the vertical series connection of multiple photodetector units, can directly improve the photoelectric conversion efficiency of the photodetector, and different numbers of photodetector film layers can also correspond to different photogenerated electromotive forces, realizing the control requirements of the photogenerated electromotive force of the photodetector.

[0035] To better understand the technical solution and effects of this application, the specific embodiments will be described in detail below with reference to the accompanying drawings.

[0036] See Figure 1 The figure is a schematic diagram of the structure of a photodetector provided in an embodiment of this application.

[0037] The photodetector 100 provided in this embodiment includes a target substrate 110 and a photodetector film 120.

[0038] Specifically, the target substrate 110 can be a semiconductor substrate, such as a silicon substrate. The number of photodetector films 120 can be multiple, that is, multiple photodetector films 120 are periodically overlapped on the target substrate 110.

[0039] In the embodiments of this application, the photodetector film 120 includes a first film layer 121, a second film layer 122, and a third film layer 123, which are doped by a first type, stacked sequentially. Specifically, one of the first type doping and the second type doping is P-type doping, and the other is N-type doping. The material of the second film layer 122 is silicon-germanium. The materials of the first film layer 121 and the third film layer 123 include at least silicon. That is, the first film layer 121 and the third film layer 123 are P-type doped or N-type doped silicon, and the material of the second film layer is silicon-germanium. The first film layer 121 and the third film layer 123 form a silicon-germanium / silicon heterojunction with the second film layer 122. That is, the photodetector film layer formed by the first film layer 121, the second film layer 122, and the third film layer 123 is an independent photodetector unit capable of realizing photoelectric signal conversion.

[0040] As one possible implementation, the first film layer of the first type of doping can be P-type doped silicon, and the second film layer of the second type of doping can be N-type doped silicon. The concentration range of P-type or N-type doping ions can be 1E19-1E22. Adjacent P-type dopants and N-type dopants form ohmic contacts, ensuring that the generated electromotive force is strictly positively correlated with the number of photodetector film layers 120.

[0041] In the embodiments of this application, since a single photodetector film layer 120 can form an independent photodetector unit, and multiple photodetector films 120 are periodically overlapped, multiple photodetector units can be vertically connected in series, enabling multiple photodetector units to perform photoelectric conversion and improving the photoelectric conversion efficiency of the photodetector 100. Furthermore, the photogenerated electromotive force generated by multiple photodetector films 120 is greater than that generated by a single photodetector film 120, and different numbers of photodetector films 120 can correspond to different photogenerated electromotive forces. Thus, the photogenerated electromotive force of the photodetector 100 can be controlled by adjusting the number of photodetector films 120.

[0042] In the embodiments of this application, the photogenerated electromotive force of the photodetector 100 is positively correlated with the number of layers of the photodetector film 120. That is, the photogenerated electromotive force of the photodetector 100 can be linearly controlled by the number of layers of the photodetector film 120. For example, the photogenerated electromotive force of the photodetector 100 can be increased by increasing the number of layers of the photodetector film 120, and the photogenerated electromotive force of the photodetector 100 can be decreased by decreasing the number of layers of the photodetector film 120.

[0043] Specifically, the number of layers in the photodetector film 120 is less than or equal to 100, meaning that the number of layers in the photodetector film 120 ranges from 0 to 100.

[0044] In the embodiments of this application, the concentration of germanium in the second film layer 122 is in the range of 0.1-0.99. That is to say, the photoelectric potential of the photodetector film layer 120 can be controlled by adjusting the concentration of germanium, thereby controlling the photoelectric potential of the overall photodetector 100.

[0045] In the embodiments of this application, the thickness of the first film layer 121, the second film layer 122, and the third film layer 123 can also affect the photogenerated electromotive force of each photodetector film layer 120. That is, the photogenerated electromotive force of the overall photodetector 100 can be controlled by adjusting the thickness of the first film layer 121, the second film layer 122, or the third film layer 123.

[0046] In embodiments of this application, the photodetector 100 may further include an isolation layer 130, as referenced. Figure 2 As shown, the isolation layer 130 is located on the sidewall of the photodetector film layer 120 and is used to protect and isolate different photodetectors 100. The material of the isolation layer 130 can be silicon nitride or silicon oxide.

[0047] In the embodiments of this application, the multilayer photodetector film 120 includes a first photodetector film 1201, which includes a first sub-film 1211 doped with a first type. The first sub-film 1211 is in contact with the target substrate 110, that is, the first sub-film 1211 is disposed on the target substrate 110. Different photodetectors 100 can use the first sub-film 1211 as a common electrically led-out film.

[0048] This application provides a photodetector, which includes: a multilayer photodetector film formed on a target substrate. The photodetector film includes a first film layer, a second film layer, and a third film layer doped with a first type of doping, stacked sequentially. One of the first type of doping and the second type of doping is P-type doped and the other is N-type doped. The material of the second film layer is silicon-germanium, and the materials of the first film layer and the second film layer include at least silicon. That is, the first film layer, the second film layer, and the third film layer doped with the first type of doping constitute a photodetector film based on a silicon-germanium / silicon heterojunction, which constitutes a photodetector unit capable of photoelectric conversion. The repeated overlapping of the multilayer photodetector film layers, i.e., the vertical series connection of multiple photodetector units, can directly improve the photoelectric conversion efficiency of the photodetector. Furthermore, different numbers of photodetector film layers can correspond to different photogenerated electromotive forces, realizing the need to control the photogenerated electromotive force of the photodetector.

[0049] Based on the photodetector provided in the above embodiments, this application also provides a method for manufacturing a photodetector, and its working principle will be described in detail below with reference to the accompanying drawings.

[0050] See Figure 3 The figure is a schematic flowchart of a method for manufacturing a photodetector provided in an embodiment of this application.

[0051] The manufacturing method of the photodetector provided in this embodiment includes the following steps:

[0052] S101, multiple photodetector films 120 are sequentially formed on the target substrate 110, with reference... Figure 5 As shown.

[0053] In the embodiments of this application, a multilayer photodetector film 120 can be sequentially formed on the target substrate 110. The photodetector film 120 includes a first film 121 doped with a first type, a second film 122 doped with a second type, and a third film 123 doped with a second type, which are stacked sequentially. One of the first type doping and the second type doping is P-type doping and the other is N-type doping. The material of the second film 122 is silicon-germanium, and the materials of the first film 121 and the third film 123 include at least silicon.

[0054] In the actual manufacturing process, reduced pressure chemical vapor deposition (RPCVD) can be used to sequentially form multiple photodetector films 120 on the target substrate 110. That is, the first film layer 121, the second film layer 122 and the third film layer 123 can be sequentially formed using the RPCVD process.

[0055] In the embodiments of this application, the multilayer photodetector film 120 includes a first photodetector film 1201, which includes a first sub-film 1211 doped with a first type. The first sub-film 1211 is in contact with the target substrate 110, that is, the first sub-film 1211 is disposed on the target substrate 110. Different photodetectors 100 can use the first sub-film 1211 as a common electrically led-out film.

[0056] Specifically, a first sub-film layer 1211 can be formed on the target substrate 110 using a doping process, see reference. Figure 4 As shown, multilayer photodetector films 120 are then formed sequentially on the first sub-film layer 1211 using depressurized chemical vapor deposition.

[0057] As an example, a first p-type doped sub-film 1211 can be formed on the target substrate 110 using a doping process, where the doping ions can be B or BF. 2+ The energy ranges from 1 keV to 100 keV, and the angle ranges from 7° to 87°. By using a doping process to form the first sub-film layer 1211, a heavy doping effect can be achieved for the first sub-film layer 1211, and the process cost is relatively low.

[0058] After forming periodically repeating photodetector layers 120 using a reduced-pressure chemical vapor deposition process, the multilayer photodetector layers 120 can be etched, specifically down to the first sub-layer 1211. Then, an isolation layer 130 is deposited. The isolation layer 130 is located on the sidewalls of the multiple photodetector layers 120, exposing the surface of the top third layer 123. (Refer to...) Figure 2 As shown.

[0059] Specifically, the thickness of the isolation layer 120 can be 5nm-100nm, and the isolation layer 130 can be formed by atomic layer deposition (ALD), low pressure chemical vapor deposition (LPCVD), or plasma enhanced chemical vapor deposition (PECVD).

[0060] As can be seen from the above process, the embodiments of this application mainly adopt the RPCVD process when forming the photodetector film 120, which can form a film with high crystal quality and realize a photodetector with high photoelectric efficiency.

[0061] In the embodiments of this application, the photogenerated electromotive force of the photodetector 100 is positively correlated with the number of layers of the photodetector film 120. That is, the photogenerated electromotive force of the photodetector 100 can be linearly controlled by the number of layers of the photodetector film 120. For example, the photogenerated electromotive force of the photodetector 100 can be increased by increasing the number of layers of the photodetector film 120, and the photogenerated electromotive force of the photodetector 100 can be decreased by decreasing the number of layers of the photodetector film 120.

[0062] Specifically, the number of layers in the photodetector film 120 is less than or equal to 100, meaning that the number of layers in the photodetector film 120 ranges from 0 to 100.

[0063] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments.

[0064] The above description is merely a preferred embodiment of this application. Although this application has disclosed preferred embodiments above, it is not intended to limit this application. Any person skilled in the art can make many possible variations and modifications to the technical solutions of this application using the methods and techniques disclosed above, or modify them into equivalent embodiments with equivalent changes, without departing from the scope of the technical solutions of this application. Therefore, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of this application without departing from the content of the technical solutions of this application shall still fall within the protection scope of the technical solutions of this application.

Claims

1. A photodetector, characterized in that, The photodetector includes: Multiple photodetector films are formed on the target substrate; The photodetector film layer includes a first film layer, a second film layer, and a third film layer doped with a first type of doping, which are stacked sequentially. One of the first type of doping and the second type of doping is P-type doping and the other is N-type doping. The material of the second film layer is silicon-germanium, and the materials of the first film layer and the third film layer include at least silicon. The first film layer is P-type doped silicon or N-type doped silicon, and the second film layer is P-type doped silicon or N-type doped silicon. The ion concentration range of P-type doping or N-type doping is 1E19-1E22, and adjacent P-type doping and N-type doping form an ohmic contact. The first film layer, the second film layer and the third film layer constitute a photodetector film based on a silicon-germanium / silicon heterojunction, serving as a photodetector unit.

2. The photodetector according to claim 1, characterized in that, The first film layer of the first type of doping is P-type doped silicon, and the second film layer of the second type of doping is N-type doped silicon.

3. The photodetector according to claim 1, characterized in that, The photogenerated electromotive force of the photodetector is positively correlated with the number of layers in the photodetector film.

4. The photodetector according to claim 3, characterized in that, The number of layers in the photoelectric detection film is less than or equal to 100.

5. The photodetector according to claim 1, characterized in that, The concentration of germanium in the second film layer ranges from 0.1 to 0.

99.

6. A method for manufacturing a photodetector, characterized in that, The method includes: Multiple photodetector films are sequentially formed on the target substrate; The photodetector film layer includes a first film layer, a second film layer, and a third film layer doped with a first type of doping, which are stacked sequentially. One of the first type of doping and the second type of doping is P-type doping and the other is N-type doping. The material of the second film layer is silicon-germanium, and the materials of the first film layer and the second film layer include at least silicon. The first film layer and the second film layer are P-type doped silicon or N-type doped silicon. The ion concentration range of P-type doping or N-type doping is 1E19-1E22, and adjacent P-type doping and N-type doping form ohmic contacts. The first film layer, the second film layer and the third film layer constitute a photodetector film based on silicon-germanium / silicon heterojunction, which serves as a photodetector unit.

7. The manufacturing method according to claim 6, characterized in that, The step of sequentially forming multiple photodetector films on the target substrate includes: Multilayer photodetector films are sequentially formed on the target substrate using depressurized chemical vapor deposition.

8. The manufacturing method according to claim 6, characterized in that, The multilayer photodetector film includes a first photodetector film, the first photodetector film including a first sub-film layer doped with a first type of doping, and the step of sequentially forming the multilayer photodetector film on the target substrate includes: The first sub-film layer is formed on the target substrate using a doping process, and multiple photodetector films are sequentially formed on the first sub-film layer using depressurized chemical vapor deposition.

9. The manufacturing method according to claim 6, characterized in that, The photogenerated electromotive force of the photodetector is positively correlated with the number of layers in the photodetector film.

10. The manufacturing method according to claim 9, characterized in that, The number of layers in the photoelectric detection film is less than or equal to 100.

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