Infrared photoelectric detector, manufacturing method thereof and electronic equipment
By adopting the design of vertical nanowire array structure and transparent conductive layer in infrared photodetector, the problems of low absorption efficiency and quantum efficiency are solved, and efficient photoelectric conversion and detection are achieved.
Patent Information
- Application Number
- CN202510837203.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-20
- Publication Date
- 2025-09-12
AI Technical Summary
Existing infrared photodetectors have problems such as low absorption efficiency, low quantum efficiency and low detection rate.
A buffer layer is grown on a substrate, and an epitaxial structure layer is formed thereon. A vertically arranged nanowire array structure is then formed on the epitaxial structure layer. Finally, a transparent conductive layer and electrodes are formed on the nanowire array structure to form an infrared photodetector.
The vertical nanowire array structure improves the light coupling efficiency of infrared photodetectors, achieves high light absorption and high quantum efficiency, and reduces reflectivity.
Smart Images
Figure CN120640812A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of semiconductors, and in particular to an infrared photoelectric detector, a manufacturing method thereof, and an electronic device. Background Art
[0002] Infrared photodetectors utilize the photoelectric effect of semiconductors for detection. When infrared light strikes the detector's photosensitive element, the photon's energy is absorbed by the photosensitive material, causing electrons in the material to transition from the valence band to the conduction band, generating electron-hole pairs. These electron-hole pairs, under the influence of an electric field, form an electric current, converting optical signals into electrical signals. However, current infrared photodetectors suffer from low absorption efficiency, low quantum efficiency, and low detectivity.
[0003] Therefore, how to solve the above technical problems should be the focus of those skilled in the art. Summary of the Invention
[0004] The purpose of this application is to provide an infrared photoelectric detector and its manufacturing method and electronic equipment to improve the absorption efficiency and quantum efficiency of the infrared photoelectric detector.
[0005] To solve the above technical problems, the present application provides a method for manufacturing an infrared photoelectric detector, comprising:
[0006] growing a buffer layer on the upper surface of the substrate;
[0007] forming an epitaxial structure layer on the upper surface of the buffer layer, and forming a nanowire array structure above the buffer layer; the nanowire array structure comprises a plurality of nanowires, each of the nanowires being perpendicular to the upper surface of the buffer layer;
[0008] forming a transparent conductive layer on the upper surface of the nanowire array structure;
[0009] A first electrode is grown on the upper surface of the transparent conductive layer, and a second electrode is grown to obtain an infrared photodetector.
[0010] As an implementation method, forming an epitaxial structure layer on the upper surface of the buffer layer, and forming a nanowire array structure above the buffer layer includes:
[0011] growing an epitaxial structure layer on the upper surface of the buffer layer, and etching the epitaxial structure layer;
[0012] a passive material layer on the upper surface of the epitaxial structure layer;
[0013] The passive material layer is etched to form the nanowire array structure.
[0014] As an implementation method, etching the passive material layer to form the nanowire array structure includes:
[0015] The passive material layer is etched by inductively coupled plasma-reactive ion etching to form the nanowire array structure, wherein the etching gas includes sulfur hexafluoride and octafluorocyclobutane gas.
[0016] As an implementation method, forming an epitaxial structure layer on the upper surface of the buffer layer, and forming a nanowire array structure above the buffer layer includes:
[0017] growing an epitaxial structure layer on the upper surface of the buffer layer;
[0018] The epitaxial structure layer is etched to form the nanowire array structure.
[0019] As an implementation method, forming an epitaxial structure layer on the upper surface of the buffer layer, and forming a nanowire array structure above the buffer layer includes:
[0020] growing an epitaxial structure layer on the upper surface of the buffer layer, and etching the epitaxial structure layer;
[0021] A plurality of the nanowires are grown on the upper surface of the epitaxial structure layer to form the nanowire array.
[0022] As an implementation method, before forming the transparent conductive layer on the upper surface of the nanowire array structure, the method further includes:
[0023] A dielectric layer is filled in the nanowire array structure.
[0024] As an implementation method, after forming a transparent conductive layer on the upper surface of the nanowire array structure, the method further includes:
[0025] growing a passivation layer on the surface of the dielectric layer and the exposed surface of the buffer layer;
[0026] At least the passivation layer located on the upper surface of the dielectric layer is removed.
[0027] As an implementation method, etching the epitaxial structure layer to form the nanowire array structure includes:
[0028] An epitaxial structure layer is formed on the upper surface of the buffer layer, and a nanowire array structure is formed above the buffer layer. The nanowire array structure includes a plurality of nanowire arrays, each of the nanowire arrays includes a plurality of nanowires, and the cross-sectional dimensions of the nanowires in different nanowire arrays are different.
[0029] The present application also provides an infrared photoelectric detector, which is manufactured using any of the above-mentioned methods for manufacturing an infrared photoelectric detector.
[0030] The present application also provides an electronic device, comprising the infrared photoelectric detector described above.
[0031] The present application provides a method for manufacturing an infrared photodetector, comprising: growing a buffer layer on the upper surface of a substrate; forming an epitaxial structure layer on the upper surface of the buffer layer, and forming a nanowire array structure above the buffer layer; the nanowire array structure comprises a plurality of nanowires, each of the nanowires being perpendicular to the upper surface of the buffer layer; forming a transparent conductive layer on the upper surface of the nanowire array structure; growing a first electrode on the upper surface of the transparent conductive layer, and growing a second electrode to obtain an infrared photodetector.
[0032] It can be seen that in the present application, when making an infrared photodetector, a buffer layer and an epitaxial structure layer are sequentially grown on a substrate, and then a nanowire array structure is formed. The nanowires are perpendicular to the upper surface of the buffer layer, that is, the nanowire array structure is a vertical nanowire array structure. The vertically arranged nanowire array structure has significant quantum effects and excellent photoelectric performance, with a large absorption cross section and strong light interaction between nanowires. Therefore, the vertical nanowire array structure has the characteristics of low reflection and strong broadband absorption, so it can increase the optical coupling of the infrared photodetector, so that the infrared photodetector achieves high light absorption and high quantum efficiency. Then, a transparent conductive layer is formed on the nanowire array structure. The transparent conductive layer can serve as a connecting medium between the first electrode and the nanowire array structure, avoiding the first electrode being formed directly above the nanowire array structure and affecting the entry and exit of light.
[0033] In addition, the present application also provides an infrared photoelectric detector and electronic equipment having the above advantages. BRIEF DESCRIPTION OF THE DRAWINGS
[0034] In order to more clearly illustrate the embodiments of the present application or the technical solutions of the prior art, the following is a brief introduction to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.
[0035] Figure 1 The manufacturing method of an infrared photoelectric detector provided in the embodiment of the present application is as follows: Figure 1 ;
[0036] Figure 2 The manufacturing method of an infrared photoelectric detector provided in the embodiment of the present application is as follows: Figure 2 ;
[0037] Figure 3 The manufacturing method of an infrared photoelectric detector provided in the embodiment of the present application is as follows: Figure 3 ;
[0038] Figure 4 The manufacturing method of an infrared photoelectric detector provided in the embodiment of the present application is as follows: Figure 4 ;
[0039] Figure 5 The manufacturing method of an infrared photoelectric detector provided in the embodiment of the present application is as follows: Figure 5 ;
[0040] Figure 6 The manufacturing method of an infrared photoelectric detector provided in the embodiment of the present application is as follows: Figure 6 ;
[0041] Figures 7 to 17 The manufacturing process of an infrared photoelectric detector provided in the embodiment of the present application is as follows Figure 1 ;
[0042] Figures 18 to 24 The manufacturing process of an infrared photoelectric detector provided in the embodiment of the present application is as follows Figure 2 ;
[0043] In the figure, 1. substrate, 2. buffer layer, 3. epitaxial structure layer, 31. n-type doped type II superlattice material bottom contact layer, 32. non-intentionally doped type II superlattice material absorption layer, 33. p-type type II superlattice material top contact layer, 4. passive material layer, 5. patterned photoresist, 6. nanowire array structure, 61. nanowire, 8. dielectric layer, 7. protective material, 9. transparent conductive layer, 10. first electrode, 11. second electrode. DETAILED DESCRIPTION
[0044] In order to enable those skilled in the art to better understand the present application, the present application is further described in detail below in conjunction with the accompanying drawings and specific embodiments. Obviously, the embodiments described are only a part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making any creative efforts are within the scope of protection of the present application.
[0045] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.
[0046] As mentioned in the background technology section, current infrared photodetectors have problems such as low absorption efficiency, low quantum efficiency and low detection rate.
[0047] In view of this, this application provides a method for manufacturing an infrared photoelectric detector, please refer to Figure 1 The method may include:
[0048] Step S101: growing a buffer layer on the upper surface of the substrate.
[0049] It should be noted that the present application does not limit the growth method of the buffer layer, which can be set at will.
[0050] In one embodiment of the present application, the buffer layer may be grown by molecular beam epitaxy (MBE).
[0051] Using molecular beam epitaxy to grow the buffer layer can improve the crystallization quality of the buffer layer, significantly reduce lattice defects (such as dislocations, grain boundaries, etc.), reduce the recombination rate of photogenerated carriers, and increase carrier mobility, thereby improving the sensitivity and response speed of the infrared detector.
[0052] The materials of the substrate and the buffer layer are not limited in this application and can be selected at will. For example, the substrate material can be GaSb (gallium antimonide) and the buffer layer material can also be GaSb.
[0053] Step S102: forming an epitaxial structure layer on the upper surface of the buffer layer, and forming a nanowire array structure above the buffer layer; the nanowire array structure includes a plurality of nanowires, each nanowire being perpendicular to the upper surface of the buffer layer.
[0054] The nanowire array structure includes at least one nanowire array, and each nanowire array includes a plurality of nanowires arranged in an array.
[0055] It should be noted that the present application does not limit the structure of the epitaxial structure layer formed, and it can be set at will.
[0056] As an implementation method, forming an epitaxial structure layer on the upper surface of the buffer layer includes:
[0057] growing a bottom contact layer on the upper surface of the buffer layer;
[0058] growing an absorber layer on the upper surface of the bottom contact layer;
[0059] A top contact layer is grown on the upper surface of the absorber layer.
[0060] Among them, the bottom contact layer can be an n-type doped type II superlattice material bottom contact layer, the absorption layer can be an unintentionally doped type II superlattice material absorption layer, and the top contact layer can be a p-type type II superlattice material top contact layer, that is, the epitaxial structure layer is a PIN structure.
[0061] It should be pointed out that the present application does not limit the type of type II superlattice material and it can be selected at will.
[0062] For example, the type II superlattice material may be InAs / GaSb, InAs / InAsSb or other antimonide type II superlattice materials, which are not specifically limited in this application.
[0063] Type II superlattice materials have the advantages of large effective mass, suppressed Auger recombination, adjustable band gap and wide wavelength coverage range. The epitaxial structure layer uses type II superlattice materials to improve the photoelectric performance of infrared photodetectors.
[0064] As an implementation method, forming an epitaxial structure layer on the upper surface of the buffer layer includes:
[0065] growing an n-type doped layer on the upper surface of the buffer layer as a bottom contact layer;
[0066] growing a barrier layer on the upper surface of the bottom contact layer;
[0067] An n-type doped layer is grown on the upper surface of the absorption layer as a top contact layer.
[0068] In this embodiment, the epitaxial structure layer adopts an nBn (n-Barrier-n, n-type doping layer-barrier layer-n-type doping layer) structure.
[0069] As an implementation method, forming an epitaxial structure layer on the upper surface of the buffer layer includes:
[0070] growing a p-type doped layer on the upper surface of the buffer layer as a bottom contact layer;
[0071] growing a barrier layer on the upper surface of the bottom contact layer;
[0072] A p-type doped layer is grown on the upper surface of the absorption layer as a top contact layer.
[0073] In this embodiment, the epitaxial structure layer adopts a pBp (p-Barrier-p, p-type doped layer-barrier layer-p-type doped layer) structure.
[0074] As an implementation method, forming an epitaxial structure layer on the upper surface of the buffer layer includes:
[0075] growing a bottom contact layer on the upper surface of the buffer layer;
[0076] growing an electron barrier layer on the upper surface of the bottom contact layer;
[0077] growing an absorption layer on the upper surface of the electron barrier layer;
[0078] growing a hole barrier layer on the upper surface of the absorption layer;
[0079] A top contact layer is grown on the upper surface of the hole barrier layer.
[0080] In this embodiment, the epitaxial structure layer includes a bottom contact layer, an electron barrier layer, an absorption layer, a hole barrier layer and a top contact layer. That is, the infrared photodetector type in this embodiment is CBIRD (Complementary Barrier Infrared Detector), which can further reduce the dark current, so that the photodetector can maintain high performance even at room temperature; and enable the photodetector to cover a wider infrared band and expand the scope of application.
[0081] As an implementation method, forming an epitaxial structure layer on the upper surface of the buffer layer includes:
[0082] growing a bottom contact layer on the upper surface of the buffer layer;
[0083] Growing a plurality of cascade structures on the upper surface of the bottom contact layer; each cascade structure includes a stacked electron barrier layer, an absorption layer, and a hole barrier layer;
[0084] A top contact layer is grown on the upper surface of the last cascade structure.
[0085] The number of cascade structures is at least two. It should be noted that the specific number of cascade structures is not limited in this application and depends on the circumstances.
[0086] In this embodiment, the epitaxial structure includes a bottom contact layer, multiple cascade structures, and a top contact layer. This means the infrared photodetector in this embodiment is an ICIP (interband cascade infrared photodetector). ICIPs employ a multi-stage short absorption region structure, which reduces recombination of photogenerated carriers and improves the detector's detectivity at high operating temperatures. This structure enables the detector to maintain high quantum efficiency even at high temperatures, avoiding the decrease in responsivity caused by a shortened diffusion length.
[0087] It should be pointed out that the present application does not limit the growth method of the epitaxial structure layer, which can be set at will.
[0088] In one embodiment of the present application, molecular beam epitaxy can be used to grow each film layer in the epitaxial structure layer to improve the crystallization quality of the film layer in the epitaxial structure layer and improve the performance of the infrared photodetector.
[0089] The nanowire array structure may be directly located on the upper surface of the buffer layer, or may be located at a certain position on the buffer layer, which is not specifically limited in this embodiment.
[0090] Nanowires have strong optical interactions with each other, and the strong optical resonance modes between nanowires are closely related to the diameter of the nanowires and the spatial distribution of the supported optical resonance modes. By designing the vertical nanowire geometry, the spectral response corresponding to the resonance mode can be changed.
[0091] It should be noted that the present application does not limit the number, cross-sectional shape and size of the nanowires in the nanowire array structure.
[0092] For example, the cross-sectional shape of the nanowire includes, but is not limited to, a circle, a triangle, a rectangle, and a hexagon. For example, from bottom to top, the size of the nanowire can be the same at all locations, or the size of the nanowire can gradually decrease, or the size of the nanowire can gradually increase, etc.
[0093] As an implementation method, the diameter of the nanowire is between tens and hundreds of nanometers, the interval between adjacent nanowires is in the order of nanometers to micrometers, and the height is in the order of micrometers.
[0094] The nanowire array structure includes at least one nanowire array, and each nanowire array includes a plurality of nanowires.
[0095] It should be noted that the present application does not limit the cross-sectional dimension relationship of nanowires in different nanowire arrays, which depends on the specific situation.
[0096] As an embodiment, the cross-sectional dimensions of the nanowires in different nanowire arrays are the same.
[0097] As another possible implementation method, an epitaxial structure layer is formed on the upper surface of the buffer layer, and a nanowire array structure is formed above the buffer layer. The nanowire array structure includes multiple nanowire arrays, each nanowire array includes multiple nanowires, and the cross-sectional dimensions of the nanowires in different nanowire arrays are different.
[0098] The cross-sectional dimensions of the nanowires in different nanowire arrays are different. By setting up multiple nanowire arrays with different geometric dimensions, selective multi-band light absorption and multi-color detection can be achieved.
[0099] Step S103: forming a transparent conductive layer on the upper surface of the nanowire array structure.
[0100] The transparent conductive layer may be an ITO (Indium tin oxide) layer or the like, which is not limited in this embodiment, as long as it is a transparent and conductive film layer.
[0101] The transparent conductive layer may be grown by sputtering or the like, which is not limited in this application.
[0102] Step S104: growing a first electrode and a second electrode on the upper surface of the transparent conductive layer to obtain an infrared photodetector.
[0103] The first electrode is a metal electrode. This application does not limit the first electrode and can be configured arbitrarily. For example, the first electrode can include a stacked titanium (Ti) layer, a platinum (Pt) layer, and a gold (Au) layer. The thickness of the titanium layer can be 50 nm, the thickness of the platinum layer can be 50 nm, and the thickness of the gold layer can be 300 nm.
[0104] The second electrode is a metal electrode. This application does not limit the second electrode and can be configured arbitrarily. For example, the second electrode can include a stacked titanium layer, a platinum layer, and a gold layer. The thickness of the titanium layer can be 50 nm, the thickness of the platinum layer can be 50 nm, and the thickness of the gold layer can be 300 nm.
[0105] It should be noted that the position of the second electrode is not limited in this application and can be set at will.
[0106] As an implementation method, the second electrode may be located on the exposed upper surface of the buffer layer.
[0107] As another possible implementation method, the second electrode may also be located on the lower surface of the substrate. The substrate is thinned, and then the second electrode is deposited on the lower surface of the substrate.
[0108] In this embodiment, when fabricating an infrared photodetector, a buffer layer and an epitaxial structure layer are sequentially grown on a substrate, followed by a nanowire array structure. The nanowires are perpendicular to the upper surface of the buffer layer, i.e., the nanowire array structure is a vertical nanowire array structure. Vertically aligned nanowire array structures exhibit significant quantum effects and excellent optoelectronic performance, with a large absorption cross-section and strong optical interaction between nanowires. Consequently, vertical nanowire array structures exhibit low reflection and strong broadband absorption, thereby increasing optical coupling in the infrared photodetector and achieving high light absorption and quantum efficiency. A transparent conductive layer is then formed on the nanowire array structure. The transparent conductive layer serves as a connecting medium between the first electrode and the nanowire array structure, preventing the first electrode from being formed directly above the nanowire array structure and thereby interfering with light ingress and egress.
[0109] Please refer to Figure 2Based on the above embodiment, in one embodiment of the present application, a method for manufacturing an infrared photoelectric detector includes:
[0110] Step S201: growing a buffer layer on the upper surface of the substrate.
[0111] Step S202: growing an epitaxial structure layer on the upper surface of the buffer layer, and etching the epitaxial structure layer.
[0112] After the epitaxial structure layer is grown, photoresist is spin-coated on the surface of the epitaxial structure layer and ultraviolet lithography and etching processes are performed to etch out the device mesa. The etching stops at the upper surface of the buffer layer, and then the photoresist is removed.
[0113] Step S203: forming a passive material layer on the upper surface of the epitaxial structure layer.
[0114] This step includes coating a protective layer on the side of the device mesa and then growing a passive material layer. The material of the passive material layer can be Si, etc., which is not specifically limited in this application.
[0115] Step S204: etching the passive material layer to form a nanowire array structure, where the nanowire array structure includes a plurality of nanowires, and each nanowire is perpendicular to the upper surface of the buffer layer.
[0116] This step includes spin coating photoresist on the surface of the passive material layer, then performing photolithography exposure and development processing, and then performing a dry etching process to obtain a plurality of vertically distributed nanowires.
[0117] In one embodiment of the present application, etching the passive material layer to form the nanowire array structure includes:
[0118] The passive material layer is etched using inductively coupled plasma-reactive ion etching to form the nanowire array structure, wherein the etching gas includes sulfur hexafluoride and octafluorocyclobutane gas. The flow rate of sulfur hexafluoride (SF6) can be 60 sccm, and the flow rate of octafluorocyclobutane gas (C4F8) can be 160 sccm.
[0119] The inductively coupled plasma-reactive ion etching method is used to generate high-density plasma, thereby significantly increasing the etching rate and improving production efficiency.
[0120] Step S205: forming a transparent conductive layer on the upper surface of the nanowire array structure.
[0121] Step S206: growing a first electrode and a second electrode on the upper surface of the transparent conductive layer to obtain an infrared photodetector.
[0122] It should be noted that, for step S201 , step S202 , step S205 and step S206 , reference may be made to the contents of the above embodiment and will not be described in detail here.
[0123] The manufacturing method in this embodiment grows a passive material layer on the upper surface of the epitaxial structure layer, and forms a nanowire array structure by etching the passive material layer.
[0124] Please refer to Figure 3 Based on the above embodiment, in one embodiment of the present application, a method for manufacturing an infrared photoelectric detector includes:
[0125] Step S301: growing a buffer layer on the upper surface of the substrate.
[0126] Step S302: growing an epitaxial structure layer on the upper surface of the buffer layer.
[0127] Step S303: etching the epitaxial structure layer to form a nanowire array structure; the nanowire array structure includes a plurality of nanowires, and each nanowire is perpendicular to the upper surface of the buffer layer.
[0128] This step includes spin coating photoresist on the epitaxial structure layer, UV exposure and development, and then etching through a dry etching process to form nanowires. The etching stops at the buffer layer and then the photoresist is removed.
[0129] In one embodiment of the present application, etching the epitaxial structure layer to form the nanowire array structure includes:
[0130] The epitaxial structure layer is etched using inductively coupled plasma (ICP) etching to form a nanowire array structure, wherein the etching gas includes BCl3 gas and Ar gas.
[0131] Step S304: forming a transparent conductive layer on the upper surface of the nanowire array structure.
[0132] Step S305: growing a first electrode and a second electrode on the upper surface of the transparent conductive layer to obtain an infrared photodetector.
[0133] It should be noted that, for step S301 , step S302 , step S304 and step S305 , reference may be made to the contents of the above embodiment and will not be described in detail here.
[0134] In this step, after the epitaxial structure layer is generated on the upper surface of the buffer layer, the epitaxial structure layer is directly etched to form nanowires, thereby obtaining a nanowire structure array.
[0135] Please refer to Figure 4Based on the above embodiment, in one embodiment of the present application, a method for manufacturing an infrared photoelectric detector includes:
[0136] Step S401: growing a buffer layer on the upper surface of the substrate.
[0137] Step S402: growing an epitaxial structure layer on the upper surface of the buffer layer, and etching the epitaxial structure layer.
[0138] In this step, the epitaxial structure layer is etched to form a device mesa.
[0139] Step S403: growing a plurality of nanowires on the upper surface of the epitaxial structure layer to form a nanowire array; the nanowire array structure includes a plurality of nanowires, and each nanowire is perpendicular to the upper surface of the buffer layer.
[0140] Step S404: forming a transparent conductive layer on the upper surface of the nanowire array structure.
[0141] Step S405: growing a first electrode and a second electrode on the upper surface of the transparent conductive layer to obtain an infrared photodetector.
[0142] It should be noted that step S401, step S402, step S404 and step S405 may refer to the contents of the above embodiment and will not be described in detail here.
[0143] In this embodiment, the nanowires are grown in a direct growth manner to obtain a nanowire array structure, which can simplify the manufacturing method.
[0144] Please refer to Figure 5 Based on any of the above embodiments, in one embodiment of the present application, a method for manufacturing an infrared photoelectric detector includes:
[0145] Step S501: growing a buffer layer on the upper surface of the substrate.
[0146] Step S502: forming an epitaxial structure layer on the upper surface of the buffer layer, and forming a nanowire array structure above the buffer layer; the nanowire array structure includes a plurality of nanowires, each nanowire being perpendicular to the upper surface of the buffer layer.
[0147] Step S503: filling a dielectric layer in the nanowire array structure.
[0148] The upper surface of the dielectric layer is flush with the upper surface of the nanowire.
[0149] The dielectric layer fills the gaps between the nanowire array structures and surrounds the periphery of the nanowire array structure.
[0150] The material of the dielectric layer is not limited in this application and can be set arbitrarily. For example, the material of the dielectric layer can be PMMA (Poly (methyl methacrylate), polymethyl methacrylate) or the like.
[0151] Step S504: forming a transparent conductive layer on the upper surface of the nanowire array structure.
[0152] Step S505: growing a first electrode and a second electrode on the upper surface of the transparent conductive layer to obtain an infrared photodetector.
[0153] It should be noted that, for step S501 , step S502 , step S504 and step S505 , reference may be made to the contents of the above embodiment, and will not be described in detail here.
[0154] In this embodiment, the filling of the dielectric layer can facilitate the subsequent production of the first electrode.
[0155] Please refer to Figure 6 Based on the above embodiment, in one embodiment of the present application, a method for manufacturing an infrared photoelectric detector includes:
[0156] Step S601: growing a buffer layer on the upper surface of the substrate.
[0157] Step S602: forming an epitaxial structure layer on the upper surface of the buffer layer, and forming a nanowire array structure above the buffer layer; the nanowire array structure includes a plurality of nanowires, each nanowire being perpendicular to the upper surface of the buffer layer.
[0158] Step S603: filling a dielectric layer in the nanowire array structure.
[0159] Step S604: forming a transparent conductive layer on the upper surface of the nanowire array structure.
[0160] Step S605: growing a passivation layer on the surface of the dielectric layer and the exposed surface of the buffer layer.
[0161] It should be noted that the material of the passivation layer is not limited in this application and can be set at will. For example, the material of the passivation layer can be silicon dioxide.
[0162] Step S606: removing at least the passivation layer located on the upper surface of the dielectric layer.
[0163] The passivation layer can be removed using photolithography and etching. When the second electrode is located in the exposed area of the buffer layer, the passivation layer located on the upper surface of the dielectric layer and the passivation layer located in the area of the buffer layer where the second electrode is to be grown need to be removed. When the second electrode is located on the lower surface of the substrate, only the passivation layer located on the upper surface of the dielectric layer needs to be removed.
[0164] Step S607: growing a first electrode and a second electrode on the upper surface of the transparent conductive layer to obtain an infrared photodetector.
[0165] It should be noted that, for step S601 , step S602 , step S603 , step S604 and step S607 , reference may be made to the contents of the above embodiment and will not be described in detail here.
[0166] In this embodiment, a passivation layer is provided for protection, thereby reducing the surface leakage current of the photodetector.
[0167] Based on the above embodiment, in one embodiment of the present application, a method for manufacturing an infrared photoelectric detector includes:
[0168] Step S701: growing a buffer layer on the upper surface of the substrate.
[0169] Step S702: forming an epitaxial structure layer on the upper surface of the buffer layer, and forming a nanowire array structure above the buffer layer; the nanowire array structure includes a plurality of nanowires, each nanowire being perpendicular to the upper surface of the buffer layer.
[0170] Step S703: filling a dielectric layer in the nanowire array structure.
[0171] Step S704: forming metal particles on the upper surface of the nanowires.
[0172] It should be noted that the metal particles are not limited in this application and can be selected at will. For example, the metal particles can be any one of gold particles, platinum particles, and silver particles, or any combination thereof.
[0173] Step S705: forming a transparent conductive layer on the upper surface of the nanowire array structure having metal particles.
[0174] Step S706: growing a first electrode and a second electrode on the upper surface of the transparent conductive layer to obtain an infrared photodetector.
[0175] It should be noted that step S701 , step S702 , step S703 , step S705 and step S706 may refer to the contents of the above embodiment and will not be described in detail here.
[0176] In this embodiment, by forming metal particles on the upper surface of the nanowire, the surface plasmon resonance effect can be utilized to generate a strong local electric field enhancement near the metal-semiconductor interface, significantly improving the photon absorption efficiency inside or near the nanowire, especially at wavelengths near the metal.
[0177] The following describes the manufacturing process of the infrared photoelectric detector in this application using different situations.
[0178] Example 1
[0179] Step 1: Figure 7 As shown, a buffer layer 2 is grown on the upper surface of the cleaned substrate 1 by molecular beam epitaxy. The material of the buffer layer 2 may be GaSb.
[0180] Step 2: Figure 8 As shown, on the upper surface of the GaSb buffer layer, a molecular beam epitaxy method is used to sequentially grow an n-type doped type II superlattice material bottom contact layer 31, an unintentionally doped type II superlattice material absorption layer 32, and a p-type type II superlattice material top contact layer 33. The n-type doped type II superlattice material bottom contact layer 31, the unintentionally doped type II superlattice material absorption layer 32, and the p-type type II superlattice material top contact layer 33 form an epitaxial structure layer 3;
[0181] Step 3: Take out the grown epitaxial wafer, clean and dry it;
[0182] Step 4: Figure 9 As shown, the epitaxial structure layer 3 is etched by spin coating photoresist, ultraviolet lithography, and etching to etch out the device mesa, and the etching stops at the buffer layer 2;
[0183] Step 5: Figure 10 As shown, a protective material 7 is coated on the side of the etched epitaxial structure layer 3, and a passive material layer 4 is formed on the upper surface of the epitaxial structure layer;
[0184] Step 6: Figure 11 and Figure 12 As shown, a photoresist is spin-coated on the upper surface of the passive material layer 4, and photolithography exposure and development processes are performed to form a patterned photoresist 5. Then, the patterned photoresist 5 is used as a mask to dry-etch the passive material layer 4 to form vertical nanowires 61, thereby obtaining a nanowire array structure 6;
[0185] Step 7: Figure 13 As shown, the patterned photoresist 5 and the protective material 7 are removed to obtain a main structure of a photodetector having a vertical nanowire array structure 6;
[0186] Step 8: Figure 14 As shown, PMMA is used to fill between the vertical nanowires 61 to form a dielectric layer 8 to facilitate the subsequent growth of the first electrode;
[0187] Step 9: Figure 15 As shown, on the upper surface of the dielectric layer 8, according to the nanowire arrays for different wavelengths, a transparent conductive layer 9 of indium tin oxide is sputtered and grown on top of each nanowire array, and the transparent conductive layer 9 serves as an electrode contact layer;
[0188] Step 10: Figure 16 and Figure 17 As shown, a first electrode 10 and a second electrode 11 are respectively grown on the upper surface of the transparent conductive layer 9 and the upper surface of the exposed buffer layer 2 to obtain an infrared photodetector, wherein the first electrode 10 and the second electrode 11 are stacked Ti / Pt / Au metal layers with corresponding thicknesses of 50nm / 50nm / 300nm.
[0189] Example 2
[0190] Step 1: Figure 7 As shown, a buffer layer 2 is grown on the upper surface of the cleaned substrate 1 by molecular beam epitaxy. The material of the buffer layer 2 may be GaSb.
[0191] Step 2: Figure 8 As shown, on the upper surface of the GaSb buffer layer, a molecular beam epitaxy method is used to sequentially grow an n-type doped type II superlattice material bottom contact layer 31, an unintentionally doped type II superlattice material absorption layer 32, and a p-type type II superlattice material top contact layer 33. The n-type doped type II superlattice material bottom contact layer 31, the unintentionally doped type II superlattice material absorption layer 32, and the p-type type II superlattice material top contact layer 33 form an epitaxial structure layer 3;
[0192] Step 3: Take out the grown epitaxial wafer, clean and dry it;
[0193] Step 4: Figure 18 As shown, a photoresist is spin-coated on the upper surface of the epitaxial structure layer 3, and ultraviolet photolithography exposure and development are performed to form a patterned photoresist 5;
[0194] Step 5: Figure 19 As shown, the patterned photoresist 5 is used as a mask, and the epitaxial structure layer is etched by a dry etching process to form vertical nanowires 61 to obtain a nanowire array structure 6, and the etching stops when the buffer layer 2 is formed;
[0195] Step 6: Figure 20 As shown, the patterned photoresist 5 and the protective material 7 are removed to obtain a main structure of a photodetector having a vertical nanowire array structure 6;
[0196] Step 7: Figure 21 As shown, PMMA is used to fill between the vertical nanowires 61 to form a dielectric layer 8 to facilitate the subsequent growth of the first electrode;
[0197] Step 8: Figure 22 As shown, on the upper surface of the dielectric layer 8, according to the nanowire arrays for different wavelengths, a transparent conductive layer 9 of indium tin oxide is sputtered and grown on top of each nanowire array, and the transparent conductive layer 9 serves as an electrode contact layer;
[0198] Step 9: Figure 23 and Figure 24 As shown, a first electrode 10 and a second electrode 11 are respectively grown on the upper surface of the transparent conductive layer 9 and the upper surface of the exposed buffer layer 2 to obtain an infrared photodetector, wherein the first electrode 10 and the second electrode 11 are stacked Ti / Pt / Au metal layers with corresponding thicknesses of 50nm / 50nm / 300nm.
[0199] The present application also provides an infrared photoelectric detector, which is manufactured using the manufacturing method of the infrared photoelectric detector of any of the above embodiments.
[0200] Please refer to Figure 17 The infrared photodetector includes a substrate 1, a buffer layer 2, an epitaxial structure layer 3, a nanowire array structure 6, a dielectric layer 8, a transparent conductive layer 9, a first electrode 10 and a second electrode 11, wherein the nanowire array structure 6 includes a plurality of nanowires 61, the nanowires are perpendicular to the upper surface of the epitaxial structure layer 3, the epitaxial structure layer 3 includes an n-type doped type II superlattice material bottom contact layer 31, an unintentionally doped type II superlattice material absorption layer 32 and a p-type type II superlattice material top contact layer 33, the nanowire array structure 6 includes a nanowire array, Figure 17 Four nanowire arrays are shown as an example. The four nanowire arrays are distributed in two rows and two columns. The buffer layer 2 is located on the upper surface of the substrate 1, the epitaxial structure layer 3 is located on the upper surface of the buffer layer 2, the nanowire array structure 6 is located on the upper surface of the epitaxial structure layer 3, the dielectric layer 8 is located around the nanowire array structure 6 and in the internal gap, the transparent conductive layer 9 is located on the upper surface of each nanowire array, the first electrode 10 is located on the upper surface of the transparent conductive layer 9, and the second electrode 11 is located on the upper surface of the buffer layer 2.
[0201] Please refer to Figure 24 The infrared photodetector includes a substrate 1, a buffer layer 2, a nanowire array structure 6, a dielectric layer 8, a transparent conductive layer 9, a first electrode 10 and a second electrode 11, wherein the nanowire array structure 6 includes a plurality of nanowires 61, the nanowires are perpendicular to the upper surface of the buffer layer 2, and the nanowire array structure 6 is obtained by etching the epitaxial structure layer 3, the epitaxial structure layer 3 includes an n-type doped type II superlattice material bottom contact layer 31, an unintentionally doped type II superlattice material absorption layer 32 and a p-type type II superlattice material top contact layer 33, and the nanowire array structure 6 includes a nanowire array. Figure 24Four nanowire arrays are shown as an example. The four nanowire arrays are distributed in two rows and two columns. The buffer layer 2 is located on the upper surface of the substrate 1, the nanowire array structure 6 is located on the upper surface of the buffer layer 2, the dielectric layer 8 is located around the nanowire array structure 6 and in the internal gap, the transparent conductive layer 9 is located on the upper surface of each nanowire array, the first electrode 10 is located on the upper surface of the transparent conductive layer 9, and the second electrode 11 is located on the upper surface of the buffer layer 2.
[0202] It should be noted that Figure 17 The epitaxial structure layer of the mid-infrared photodetector can also be other forms of epitaxial structure layers, and Figure 24 The nanowires can also be obtained by etching other forms of epitaxial structure layers, which include an n-type doped layer as a bottom contact layer, a barrier layer and an n-type doped layer as a top contact layer, or a p-type doped layer as a bottom contact layer, a barrier layer and a p-type doped layer as a top contact layer, or a bottom contact layer, an electron barrier layer, an absorption layer, a hole barrier layer and a top contact layer, or a bottom contact layer, multiple cascade structures and a top contact layer, each cascade structure including a stacked electron barrier layer, an absorption layer and a hole barrier layer.
[0203] It should also be noted that Figure 17 and Figure 24 The second electrode 11 of the mid-infrared photodetector may also be located on the lower surface of the substrate 1 .
[0204] The present application also provides an electronic device, which includes the infrared photodetector of the above embodiment.
[0205] The type of electronic device is not limited in this application. For example, the electronic device may be an infrared imaging device, a free-space optical communication device, a frequency comb spectrometer, etc.
[0206] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.
[0207] The above is a detailed introduction to the infrared photoelectric detector, its manufacturing method, and electronic device provided by this application. Specific examples are used herein to illustrate the principles and implementation methods of this application. The description of the above embodiments is only used to help understand the method and core ideas of this application. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of this application, several improvements and modifications can be made to this application, and these improvements and modifications also fall within the scope of protection of this application.
Claims
1. A method for manufacturing an infrared photoelectric detector, characterized in that: include: growing a buffer layer on the upper surface of the substrate; forming an epitaxial structure layer on the upper surface of the buffer layer, and forming a nanowire array structure above the buffer layer; the nanowire array structure comprises a plurality of nanowires, each of the nanowires being perpendicular to the upper surface of the buffer layer; forming a transparent conductive layer on the upper surface of the nanowire array structure; A first electrode is grown on the upper surface of the transparent conductive layer, and a second electrode is grown to obtain an infrared photodetector.
2. The method for manufacturing an infrared photodetector according to claim 1, wherein: Forming an epitaxial structure layer on the upper surface of the buffer layer and forming a nanowire array structure above the buffer layer includes: growing an epitaxial structure layer on the upper surface of the buffer layer, and etching the epitaxial structure layer; a passive material layer on the upper surface of the epitaxial structure layer; The passive material layer is etched to form the nanowire array structure.
3. The method for manufacturing an infrared photodetector according to claim 2, wherein: Etching the passive material layer to form the nanowire array structure includes: The passive material layer is etched by inductively coupled plasma-reactive ion etching to form the nanowire array structure, wherein the etching gas includes sulfur hexafluoride and octafluorocyclobutane gas.
4. The method for manufacturing an infrared photodetector according to claim 1, wherein: Forming an epitaxial structure layer on the upper surface of the buffer layer and forming a nanowire array structure above the buffer layer includes: growing an epitaxial structure layer on the upper surface of the buffer layer; The epitaxial structure layer is etched to form the nanowire array structure.
5. The method for manufacturing an infrared photodetector according to claim 1, wherein: Forming an epitaxial structure layer on the upper surface of the buffer layer and forming a nanowire array structure above the buffer layer includes: growing an epitaxial structure layer on the upper surface of the buffer layer, and etching the epitaxial structure layer; A plurality of the nanowires are grown on the upper surface of the epitaxial structure layer to form the nanowire array.
6. The method for manufacturing an infrared photodetector according to claim 1, wherein: Before forming a transparent conductive layer on the upper surface of the nanowire array structure, the method further includes: A dielectric layer is filled in the nanowire array structure.
7. The method for manufacturing an infrared photodetector according to claim 6, wherein: After forming a transparent conductive layer on the upper surface of the nanowire array structure, the method further includes: growing a passivation layer on the surface of the dielectric layer and the exposed surface of the buffer layer; At least the passivation layer located on the upper surface of the dielectric layer is removed.
8. The method for manufacturing an infrared photodetector according to any one of claims 1 to 7, wherein: Forming an epitaxial structure layer on the upper surface of the buffer layer and forming a nanowire array structure above the buffer layer includes: An epitaxial structure layer is formed on the upper surface of the buffer layer, and a nanowire array structure is formed above the buffer layer. The nanowire array structure includes a plurality of nanowire arrays, each of the nanowire arrays includes a plurality of nanowires, and the cross-sectional dimensions of the nanowires in different nanowire arrays are different.
9. An infrared photoelectric detector, characterized in that: The infrared photoelectric detector is manufactured by the manufacturing method of the infrared photoelectric detector according to any one of claims 1 to 8.
10. An electronic device, characterized in that: Comprising the infrared photodetector as claimed in claim 9.