Infrared detector and method of manufacturing the same

Abstract

The application discloses an infrared detector and a manufacturing method thereof. The N-type absorption layer (12) of the infrared detector is N-type InAs material or N-type InAs / InPSb superlattice, and the N-type barrier layer (13) of the infrared detector is N-type InPSb material. The device structure of the application does not contain Al at all, avoids oxidation of the Al-containing material, reduces the difficulty of material growth and processing, and improves the stability and reliability of the device.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of optoelectronics and semiconductor technology, and particularly relates to an infrared detector and a manufacturing method thereof. BACKGROUND

[0002] Short-wave infrared detectors have a cut-off wavelength ranging from 1 micrometer to 3 micrometers, and can be used in the fields of optical fiber communication, security and protection imaging, industrial detection, gas detection, etc., and have a wide application prospect and important commercial value. At present, common short-wave infrared detectors are mainly based on indium gallium arsenide (InGaAs) materials and mercury cadmium telluride (HgCdTe) materials. The InGaAs material has the best performance at 1.7 micrometers, at which the InGaAs material is lattice-matched with an indium phosphide (InP) substrate. However, due to the material quality, the performance of the InGaAs detector sharply decreases when the wavelength is extended to 2 micrometers to 3 micrometers. The HgCdTe material has good quality and long minority carrier lifetime, and the short-wave detector prepared therefrom has excellent performance, but is mainly limited to military use at present because of the high price of the material.

[0003] Sb) material, for example, AlSb or AlAsSb, to tune the wavelength by means of AlSb to achieve detection of 1 micrometer to 3 micrometers. However, the Al-containing material is prone to oxidation, which increases the difficulty of growth and processing of the infrared detector and affects the stability of the device. SUMMARY

[0004] In order to solve the above technical problems existing in the prior art, the present application provides an infrared detector free of Al and a manufacturing method thereof.

[0005] According to an aspect of an embodiment of the present application, there is provided an infrared detector, wherein the N-type absorption layer of the infrared detector is an N-type InAs material or an N-type InAs / InPSb superlattice, and the N-type barrier layer of the infrared detector is an N-type InPSb material.

[0006] In one example of the infrared detector provided in the above aspect, the band width of the N-type barrier layer is greater than the effective band width of the N-type absorption layer, and the valence band of the N-type barrier layer is flush with the valence band of the N-type absorption layer.

[0007] In one example of the infrared detector provided in the above aspect, the infrared detector further comprises a substrate, an N-type contact layer, a P-type contact layer, a first electrode and a second electrode; wherein the N-type contact layer, the N-type absorption layer, the N-type barrier layer and the P-type contact layer are sequentially stacked on the substrate in a direction away from the substrate, the first electrode is in contact with the N-type contact layer, and the second electrode is disposed on the P-type contact layer.

[0008] In one example of the infrared detector provided in the above aspect, a portion of the N-type absorption layer, the N-type barrier layer and the P-type contact layer are etched to form a mesa structure exposing the N-type contact layer, and the first electrode is disposed on the exposed N-type contact layer.

[0009] In one example of the infrared detector provided in the above aspect, the substrate is an N-type InAs substrate or an N-type GaSb substrate, and / or the N-type contact layer is an N-type InAs material or an N-type InAsSb material, and / or the P-type contact layer is a P-type InPSb material or a P-type GaSb material.

[0010] According to another aspect of the embodiments of the present application, a method for manufacturing an infrared detector is provided, which comprises: using an N-type InAs material or an N-type InAs / InPSb superlattice to manufacture an N-type absorption layer of the infrared detector, and using an N-type InPSb material to manufacture an N-type barrier layer of the infrared detector.

[0011] In one example of the method for manufacturing an infrared detector provided in the above aspect, the N-type barrier layer has a wider bandwidth than an effective bandwidth of the N-type absorption layer, and a valence band of the N-type barrier layer is flush with a valence band of the N-type absorption layer.

[0012] In one example of the method for manufacturing an infrared detector provided in the above aspect, before the N-type absorption layer is manufactured, the method further comprises: manufacturing an N-type contact layer on a substrate; using an N-type InAs material or an N-type InAs / InPSb superlattice to manufacture the N-type absorption layer of the infrared detector, specifically comprising: using the N-type InAs material or the N-type InAs / InPSb superlattice to manufacture the N-type absorption layer on the N-type contact layer; using an N-type InPSb material to manufacture the N-type barrier layer of the infrared detector, specifically comprising: using the N-type InPSb material to manufacture the N-type barrier layer on the N-type absorption layer; after the N-type barrier layer is manufactured, the method further comprises: manufacturing a P-type contact layer on the N-type barrier layer; depositing a first electrode in contact with the N-type contact layer, and depositing a second electrode on the P-type contact layer.

[0013] In one example of the method for manufacturing the infrared detector provided in the above-mentioned another aspect, the depositing the first electrode in contact with the N-type contact layer specifically comprises: locally etching the P-type contact layer, the N-type barrier layer and the N-type absorption layer to form a mesa structure exposing the N-type contact layer; and depositing the first electrode on the exposed N-type contact layer.

[0014] In one example of the method for manufacturing the infrared detector provided in the above-mentioned another aspect, the substrate is an N-type InAs substrate or an N-type GaSb substrate, and / or the N-type contact layer is an N-type InAs material or an N-type InAsSb material, and / or the P-type contact layer is a P-type InPSb material or a P-type GaSb material.

[0015] Beneficial effects: The infrared detector of the present application does not contain Al at all, avoiding the oxidation of Al-containing materials, reducing the difficulty of material growth and processing, and improving the stability and reliability of the device. BRIEF DESCRIPTION OF DRAWINGS

[0016] The above and other aspects, features and advantages of embodiments of the present application will become more apparent from the following description taken in conjunction with the accompanying drawings, in which:

[0017] Figure 1 is a structural schematic diagram of an infrared detector according to an embodiment of the present application;

[0018] Figure 2 is a band diagram of an infrared detector according to an embodiment of the present application;

[0019] Figure 3 is a relative position comparison diagram of the conduction band E C and the valence band E V of the InPSb barrier layer and the InAs / InPSb superlattice in the infrared detector according to an embodiment of the present application;

[0020] Figures 4a to 4d is a flowchart of a method for manufacturing an infrared detector according to an embodiment of the present application. DETAILED DESCRIPTION

[0021] Hereinafter, specific embodiments of the present application will be described in detail with reference to the accompanying drawings. However, the present application can be implemented in many different forms and should not be construed as limited to the specific embodiments set forth herein. Rather, these embodiments are provided so that the principles of the present application can be understood and the various embodiments of the present application and various modifications for a specific intended application can be derived from the teachings thereon by other skilled persons.

[0022] As used herein, the terms "includes," "including," "has," "having," "contains," "containing," "comprises," "comprising," "may" and "including," are open-ended terms. The term "based on" is the same as "based at least in part on." The terms "embodiment," "one embodiment," "an embodiment," "one example," and "an example," mean "at least one embodiment." The terms "another embodiment," "a further embodiment," "another example," and "a further example," mean "at least one additional embodiment." The terms "a first," "a second," "the first," "the second," "the third," "the fourth," etc., and the like, as used in the specification and in claims, do not imply that there are only one first and one second, etc., entity. The foregoing are merely examples of how certain terms are used throughout the specification and claims. Other terms are to be interpreted similarly. Other definitions of the terms will also be apparent to those skilled in the art upon reading the present specification and will be appreciated to be included in the present application. Unless otherwise indicated, the definitions apply throughout this specification and claims.

[0023] It should also be noted that, in order to avoid obscuring the present application with unnecessary details, only the structures and / or processing steps closely related to the solution according to the present application are shown in the drawings, while other details that are not closely related are omitted.

[0024] As described in the background section, the existing short-wave antimonide infrared detector basically uses Al-containing materials, such as AlSb or AlAsSb, but the Al-containing materials are extremely easy to oxidize, which increases the difficulty of growth and processing of the infrared detector and affects the stability of the device.

[0025] Therefore, in order to solve the above problems, the embodiments according to the present application provide an infrared detector and a manufacturing method thereof. In the infrared detector, Al-free InPSb is used as an electron barrier layer, and Al-free InAs / InPSb superlattice is used as an absorption layer, which makes good use of the advantage of InPSb as a natural electron barrier of InAs material. Therefore, the embodiments according to the present application provide an antimonide infrared detector without Al, so that the difficulty of growth and processing of the infrared detector can be reduced, and the stability of the device will not be affected.

[0026] The infrared detector according to the embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0027] Figure 1 is a structural schematic diagram of the infrared detector according to the embodiments of the present application.

[0028] Referring to Figure 1 As shown in the drawings, the infrared detector provided by the embodiments according to the present application comprises: a substrate 10; an N-type contact layer 11, an N-type absorption layer 12, an N-type barrier layer 13 and a P-type contact layer 14 which are stacked on the substrate 10 from bottom to top (i.e., sequentially stacked in the direction away from the substrate); and a first electrode 15 and a second electrode 16; wherein the first electrode 15 is arranged on the N-type contact layer 11, and the second electrode 16 is arranged on the P-type contact layer 14.

[0029] In one example, the substrate 10 can be an N-type InAs substrate or an N-type GaSb substrate.

[0030] In one example, the N-type contact layer 11 can be an N-type InAs or N-type InAsSb material, the thickness of the N-type contact layer 11 can be 0.2 μm to 0.5 μm, the doping source can be selected from Si or Te, and the doping concentration can be 1 x 1018cm-3to 1 x 1020cm-3. 18 -3 19 -3

[0031] In one example, the N-type absorption layer 12 can be an N-type InAs material or an N-type InAs / InPSb superlattice, the thickness of the N-type absorption layer 12 can be 2 μm to 5 μm, the doping source can be selected from Si or Te, and the doping concentration can be 1 x 1018cm-3to 1 x 1020cm-3. 16 -3 17 -3 The corresponding bandwidth can be 0.4 eV to 0.6 eV.

[0032] In one example, the N-type barrier layer 13 can be an N-type InPSb material, the thickness of the N-type barrier layer 13 can be 0.1 μm to 0.5 μm, the doping source can be selected from Si or Te, and the doping concentration can be 5 x 1018cm-3to 2 x 1020cm-3. 15 -3 16 -3

[0033] In one example, the P-type contact layer 14 can be a P-type InPSb or P-type GaSb material, the thickness of the P-type contact layer 14 can be 0.2 μm to 0.5 μm, the doping source can be selected from Zn or Be, and the doping concentration can be 1 x 1018cm-3to 1 x 1020cm-3. 18 -3 19 -3

[0034] The energy band of the infrared detector according to the embodiment of the present application is described in detail below. Figure 2 is a schematic diagram of the energy band of the infrared detector according to the embodiment of the present application.

[0035] Referring to Figure 1 and Figure 2 , the bandwidth of the N-type barrier layer 13 is greater than the effective bandwidth of the N-type absorption layer 12, and the valence band E V of the N-type barrier layer 13 is higher than the valence band E V ​​​​​​​​​​​​​​​The N-type contact layer 11 and the P-type contact layer 14 are aligned, forming an electron barrier. Thus, when the device is operating, noise hot electrons generated in the N-type absorption layer 12 are blocked by the potential barrier of the N-type barrier layer 13, effectively suppressing the device's dark current. Simultaneously, for electron-hole pairs generated by the absorption of light signals by the N-type absorption layer 12, electrons are collected by the N-type contact layer 11, while holes are collected by the P-type contact layer 14 after crossing the N-type barrier layer 13. In other words, the heterostructure containing an electron barrier can suppress the detector's dark current and noise while also ensuring normal absorption of photocurrent, thereby improving the detection performance of the infrared detector.

[0036] The existing short-wavelength antimonide infrared detectors contain Al in both the barrier layer and the absorption layer. In the infrared detector according to the embodiment of the present invention, Al-free InPSb is used as the electron barrier layer (i.e., N-type barrier layer 13), and Al-free InAs / InPSb superlattice is used as the absorption layer (i.e., N-type absorption layer 12), which makes good use of the advantage of InPSb as the natural electron barrier of InAs material. Its energy band arrangement is as follows: Figure 3 shown. Figure 3 is the conduction band E of the InPSb barrier layer and the InAs / InPSb superlattice in the infrared detector according to the embodiment of the present invention. C and valence band E V Relative position comparison diagram.

[0037] Reference Figure 3 , the valence band E of InPSb material and InAs material V Natural flush, conduction band E C The difference is 0.2eV. The valence band E of InAs / InPSb superlattice after forming microband V E of the InPSb barrier V flat, forming an ideal electron barrier heterojunction, the conduction band E C It is between InAs and InPSb, and the absorption wavelength can be flexibly adjusted by thickness. The cut-off wavelength is 2 microns to 3 microns, which can cover most of the short-wave infrared range.

[0038] The following describes in detail the manufacturing process of the infrared detector according to the embodiment of the present invention. Figures 4a to 4d 4 is a process diagram of a method for manufacturing an infrared detector according to an embodiment of the present invention.

[0039] Reference Figure 4a , providing a substrate 10. In one example, the substrate 10 can be an N-type InAs substrate or an N-type GaSb substrate.

[0040] Reference Figure 4b An N-type contact layer 11 , an N-type absorption layer 12 , an N-type barrier layer 13 , and a P-type contact layer 14 are sequentially grown on the substrate 10 from bottom to top to form a stacked layer.

[0041] In one example, a metal organic chemical vapor deposition (MOCVD) process is used to sequentially grow an N-type contact layer 11, an N-type absorption layer 12, an N-type barrier layer 13, and a P-type contact layer 14 on the substrate 10 from bottom to top. Specifically, the metal organic chemical vapor deposition process is used as the growth process, the growth sources are TMIn, TMSb, AsH3, and PH3, the n-type doping source is SiH4, the p-type doping source is DEZn, the growth temperature is set to about 600°C, and the reaction chamber pressure is set to 200 Torr. After the high temperature treatment removes the impurities on the surface of the substrate 10 in step S1, the following are sequentially grown on the substrate 10 from bottom to top:

[0042] (1) N-type contact layer 11. In one example, the N-type contact layer 11 is made of N-type InAs material with a thickness of 0.2 μm and doped with Si at a doping concentration of 1×10 18 cm -3 .

[0043] (2) N-type absorption layer 12. In one example, the N-type absorption layer 12 is made of N-type InAs material with a thickness of 2 μm and doped with Si at a doping concentration of 1×10 16 cm -3 , corresponding to a bandwidth of 0.4 eV.

[0044] (3) N-type barrier layer 13. In one example, the N-type barrier layer 13 is made of N-type InPSb material with a thickness of 0.1 μm and doped with Si at a doping concentration of 5×10 15 cm -3 .

[0045] (4) P-type contact layer 14. In one example, the P-type contact layer 14 is made of P-type InPSb material with a thickness of 0.2 μm and doped with Zn at a doping concentration of 1×10 18 cm.

[0046] Here, the MOCVD process is used to grow the N-type contact layer 11, N-type absorption layer 12, N-type barrier layer 13, and P-type contact layer 14. The resulting infrared detector has a cutoff wavelength of approximately 3μm. Due to the high throughput and low cost of the MOCVD process, adopting this process can reduce costs and improve the cost-effectiveness of the manufactured infrared detector.

[0047] In another example, a molecular beam epitaxy process is used as the growth process, with solid-state elemental sources Ga, In, As, P, and Sb as the growth source, Te as the n-type doping source, Be as the p-type doping source, and a growth temperature of approximately 400° C. After the substrate 10 is degassed and impurities are removed, the following are grown on the substrate 10 from bottom to top:

[0048] (1) N-type contact layer 11. In one example, the N-type contact layer 11 is N-type InAsSb material, 0.5 μm in thickness, doped with Te, and 1 x 1018cm-3 in doping concentration. 19 cm -3 .

[0049] (2) N-type absorption layer 12. In one example, the N-type absorption layer 12 is N-type InAs / InPSb superlattice, 5 μm in thickness, doped with Te, and 1 x 1018cm-3 in doping concentration. 17 cm -3 , with a corresponding bandwidth of 0.5 eV.

[0050] (3) N-type barrier layer 13. In one example, the N-type barrier layer 13 is N-type InPSb material, 0.5 μm in thickness, doped with Te, and 2 x 1018cm-3 in doping concentration. 16 cm -3 .

[0051] (4) P-type contact layer 14. In one example, the P-type contact layer 14 is P-type GaSb material, 0.5 μm in thickness, doped with Be, and 1 x 1018cm-3 in doping concentration. 19 cm -3 .

[0052] In the case of using MBE process as the growth process, the cutoff wavelength of the infrared detector obtained is about 2.5 μm. Since MBE process can form steep interfaces, the short-wave infrared detector obtained by this process has higher performance.

[0053] Referring to Figure 4c , the P-type contact layer 14, the N-type barrier layer 13, and the N-type absorption layer 12 are locally etched to form a mesa structure A exposing the N-type contact layer 11.

[0054] In one example, the P-type contact layer 14, the N-type barrier layer 13, and the N-type absorption layer 12 are locally etched by using an inductively coupled plasma etching (ICP) process to expose the N-type contact layer 11, thereby forming the mesa structure A.

[0055] In another example, the P-type contact layer 14, the N-type barrier layer 13, and the N-type absorption layer 12 are locally etched by using a wet etching process to expose the N-type contact layer 11, thereby forming the mesa structure A.

[0056] Referring to Figure 4d , a first electrode 15 is deposited on the N-type contact layer 11, and a second electrode 16 is deposited on the P-type contact layer 14.

[0057] In one example, the first electrode 15 is deposited on the exposed N-type contact layer 11 and the second electrode 16 is deposited on the P-type contact layer 14 by an electron beam evaporation process. In this example, the first electrode 15 and the second electrode 16 are both Ti / Pt / Au combinations.

[0058] In another example, the first electrode 15 is deposited on the exposed N-type contact layer 11 and the second electrode 16 is deposited on the P-type contact layer 14 by an electron beam evaporation process. In this example, the first electrode 15 and the second electrode 16 are both Ti / Pt / Au combinations.

[0059] In summary, the infrared detector and the manufacturing method thereof according to the embodiments of the present application do not contain Al in the device structure, avoid the oxidation of Al-containing materials, reduce the difficulty of material growth and processing, and improve the stability and reliability of the device.

[0060] The terms "exemplary," "example," and the like are used as adjectives to indicate that something is used as an example, instance, or illustration. Such terms do not necessarily convey a preference or advantage over other embodiments. The detailed description includes specific details for the purpose of providing a thorough understanding of the described techniques. However, these techniques can be practiced without these specific details. In some instances, well-known structures and devices are shown in block diagram form in order to avoid obscuring the concepts of the described embodiments.

[0061] The above describes optional embodiments of the embodiments of the present application in detail in combination with the drawings, but the embodiments of the present application are not limited to the specific details in the above-described embodiments. Within the technical concept scope of the embodiments of the present application, the technical solutions of the embodiments of the present application can be subjected to various simple modifications, and these simple modifications all belong to the protection scope of the embodiments of the present application.

[0062] The above description of the content of the present specification is provided so that any ordinary person skilled in the art can implement or use the content of the present specification. Various modifications to the content of the present specification are obvious to those skilled in the art, and the general principles defined herein can also be applied to other variations without departing from the protection scope of the content of the present specification. Therefore, the content of the present specification is not limited to the examples and designs described herein, but is consistent with the broadest scope that conforms to the principles and novel features disclosed herein.

Claims

1. An infrared detector, characterized in that: include: A substrate (10), an N-type contact layer (11), an N-type absorption layer (12), an N-type barrier layer (13), a P-type contact layer (14), a first electrode (15), and a second electrode (16); The N-type contact layer (11), the N-type absorption layer (12), the N-type barrier layer (13), and the P-type contact layer (14) are sequentially stacked on the substrate (10) in a direction away from the substrate (10); the first electrode (15) is in contact with the N-type contact layer (11); and the second electrode (16) is arranged on the P-type contact layer (14); The N-type absorption layer (12) of the infrared detector is an N-type InAs material or an N-type InAs / InPSb superlattice, and the N-type barrier layer (13) of the infrared detector is an N-type InPSb material.

2. The infrared detector according to claim 1, characterized in that: The bandwidth of the N-type barrier layer (13) is greater than the effective bandwidth of the N-type absorption layer (12), and the valence band of the N-type barrier layer (13) is aligned with the valence band of the N-type absorption layer (12).

3. The infrared detector according to claim 1, characterized in that: The N-type absorption layer (12), the N-type barrier layer (13), and a portion of the P-type contact layer (14) are etched away to form a mesa structure (A) exposing the N-type contact layer (11); the first electrode (15) is arranged on the exposed N-type contact layer (11).

4. The infrared detector according to claim 1, characterized in that: The substrate (10) is an N-type InAs substrate or an N-type GaSb substrate, and / or the N-type contact layer (11) is an N-type InAs material or an N-type InAsSb material, and / or the P-type contact layer (14) is a P-type InPSb material or a P-type GaSb material.

5. A method for manufacturing an infrared detector, characterized in that: include: Forming an N-type contact layer (11) on a substrate (10); An N-type absorption layer (12) is formed on the N-type contact layer (11) using an N-type InAs material or an N-type InAs / InPSb superlattice; An N-type barrier layer (13) is formed on the N-type absorption layer (12) using an N-type InPSb material; forming a P-type contact layer (14) on the N-type barrier layer (13); A first electrode (15) in contact with the N-type contact layer (11) is formed by deposition, and a second electrode (16) is formed on the P-type contact layer (14).

6. The method for manufacturing an infrared detector according to claim 5, wherein: The bandwidth of the N-type barrier layer (13) is greater than the effective bandwidth of the N-type absorption layer (12), and the valence band of the N-type barrier layer (13) is aligned with the valence band of the N-type absorption layer (12).

7. The method for manufacturing an infrared detector according to claim 5, wherein: The deposition forming the first electrode (15) in contact with the N-type contact layer (11) specifically includes: Partially etching the P-type contact layer (14), the N-type barrier layer (13), and the N-type absorption layer (12) to form a mesa structure (A) exposing the N-type contact layer (11); A first electrode (15) is deposited on the exposed N-type contact layer (11).

8. The method for manufacturing an infrared detector according to claim 5, wherein: The substrate (10) is an N-type InAs substrate or an N-type GaSb substrate, and / or the N-type contact layer (11) is an N-type InAs material or an N-type InAsSb material, and / or the P-type contact layer (14) is a P-type InPSb material or a P-type GaSb material.

Images