A monolithic in-situ integrated light emission and self-driven detection device and its fabrication method

Abstract

This invention relates to the field of semiconductor technology and discloses a monolithic in-situ integrated light-emitting and self-driven detection device and its fabrication method, comprising a self-driven ultraviolet detector and an ultraviolet LED sequentially connected along the epitaxial growth direction; the self-driven ultraviolet detector is an Al x Ga 1‑x N / Al y Ga 1‑y N-type heterojunction structure. This invention not only allows for in-situ integration with LEDs and simplifies the manufacturing process, but also fully utilizes the inherent polarization effect of III-V group nitrides to achieve self-driven detection. This not only broadens the detection wavelength range but also completely avoids the Stokes shift problem in traditional on-chip optical chips, improving the detection capability of the on-chip system. This invention thus solves the problems of low light-dark-current ratio and poor communication efficiency in existing technologies, and has the characteristic of avoiding the Stokes shift problem.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, and more specifically, to a monolithic in-situ integrated light-emitting and self-driven detection device and its fabrication method. Background Technology

[0002] Compared to traditional wireless radio frequency communication, wireless optical communication technology has advantages such as large channel capacity, strong resistance to electromagnetic interference, and flexible networking, making it a key solution for 6G mobile communication. Furthermore, the wavelength range of 200nm to 280nm falls into the solar blind band, thus ultraviolet light communication technology features low noise interference and low detectability, ensuring the security and confidentiality of data transmission.

[0003] Furthermore, research on ultraviolet emission and detection has attracted widespread attention, with monolithically integrated full-duplex communication of emission and detection being a particularly hot research topic. This monolithic integration offers the following advantages: a) enabling the detection of signal states; b) providing better compactness, robustness, and multifunctionality compared to external detection devices. Currently, AlGaN materials are widely used to fabricate ultraviolet light sources and ultraviolet detection devices because AlGaN is not only a direct bandgap semiconductor, but its bandgap of 3.42 eV to 6.20 eV covers most of the ultraviolet band. Through researchers' unremitting efforts, on-chip ultraviolet emission and detection functions can be achieved using multiple epitaxial growth techniques; however, this method significantly increases the complexity and technical difficulty of the process. Therefore, researchers have begun to utilize the physical properties of multiple quantum wells, which allow for the simultaneous emission and detection capabilities, to achieve monolithic in-situ integration of ultraviolet emission and detection functions.

[0004] However, this identical light-emitting and detection structure faces a severe Stokes shift problem, where the detection and emission spectra are spatially separated. This is highly detrimental to the on-chip system's detection response, leading to a low photocurrent-to-dark ratio and poor communication efficiency. Although researchers have proposed optimizing the quantum well region structure to modulate the emission and detection spectra and alleviate the Stokes shift problem, it is difficult to fundamentally avoid and solve this critical issue.

[0005] In summary, how to invent a light-emitting and detection model with a high light-dark current ratio and good communication efficiency is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0006] In order to solve the problems of low light-dark-current ratio and poor communication efficiency in the prior art, the present invention provides a monolithic in-situ integrated light emission and self-driven detection device, which has the feature of avoiding Stokes displacement problem.

[0007] To achieve the above-mentioned objectives of this invention, the technical solution adopted is as follows:

[0008] A monolithic in-situ integrated light-emitting and self-driven detection device includes a self-driven ultraviolet detector and an ultraviolet LED connected sequentially along the epitaxial growth direction; the self-driven ultraviolet detector is an Al x Ga 1-x N / Al y Ga 1-y N heterojunction structure.

[0009] Preferably, the self-driven ultraviolet detector specifically includes Al x Ga 1-x N-absorbing layer and Al y Ga 1-y N layer; Al y Ga 1-y The first ohmic electrode is located on the N layer, Al x Ga 1-x A second ohmic electrode is provided on the N-absorbent layer.

[0010] Furthermore, Al x Ga 1-x In the N-absorbing layer, the coefficients of each component are 0≤x≤1 and 0≤1-x≤1, and its thickness is 5nm~5μm; Al y Ga 1-y In the N-layer, the coefficients of each component are 0≤y≤1 and 0≤1-y≤1, and its thickness is 5nm~5μm, where x>y.

[0011] Furthermore, the ultraviolet LED includes an N-type semiconductor transport layer, a multiple quantum well layer, a P-type electron blocking layer, a P-type semiconductor transport layer, and an insulating layer; the N-type semiconductor transport layer is provided with a P-type ohmic electrode, and the P-type semiconductor transport layer is provided with an N-type ohmic electrode.

[0012] Furthermore, it also includes a substrate, a buffer layer, and a metal reflective layer;

[0013] Substrate, buffer layer, Al x Ga 1-x N-absorbing layer, Al y Ga 1-y The N-layer, N-type semiconductor transport layer, multiple quantum well layer, P-type electron blocking layer, P-type semiconductor transport layer, insulating layer, and metal reflective layer are arranged sequentially along the epitaxial growth direction.

[0014] Furthermore, the substrate material is sapphire, AlN, GaN, Si, or SiC, and is classified into polar substrates and semi-polar substrates according to the epitaxial growth direction.

[0015] Furthermore, the material of the buffer layer is Al. x1 In y1 Ga1-x1-y1 N, where the component coefficients are 0 ≤ x1 ≤ 1, 0 ≤ y1 ≤ 1, 0 ≤ 1 - x1 - y1 ≤ 1, and its thickness is 10 - 500 nm; the Al x Ga 1-x In the N absorption layer, the component coefficients are 0 ≤ x ≤ 1, 0 ≤ 1 - x ≤ 1, and its thickness is 5 nm - 5 μm; the Al y Ga 1-y In the N layer, the component coefficients are 0 ≤ y ≤ 1, 0 ≤ 1 - y ≤ 1, where x < y, and its thickness is 5 nm - 5 μm; the material of the N-type semiconductor transport layer is Al x2 In y2 Ga 1-x2-y2 N, where the component coefficients are 0 ≤ x2 ≤ 1, 0 ≤ y2 ≤ 1, 0 ≤ 1 - x2 - y2 ≤ 1, and its thickness is 500 nm - 5 μm.

[0016] Furthermore, the structure of the multiple quantum well layer is Al x3 In y3 Ga 1-x3-y3 N / Al x4 In y4 Ga 1-x4-y4 N, where the component coefficients are 0 ≤ x3 ≤ 1, 0 ≤ y3 ≤ 1, 0 ≤ 1 - x3 - y3 ≤ 1, 0 ≤ x4 ≤ 1, 0 ≤ y4 ≤ 1, 0 ≤ 1 - x4 - y4 ≤ 1, the bandgap of the quantum barrier is greater than that of the quantum well, the number of quantum wells is greater than or equal to 1, the thickness of the quantum well Al x3 In y3 Ga 1-x3-y3 N is 1 - 20 nm, and the thickness of the quantum barrier Al x4 In y4 Ga 1-x4-y4 N is 5 - 50 nm.

[0017] Furthermore, the material of the P-type electron blocking layer is Al x5 In y5 Ga 1-x5-y5 N, where the component coefficients are 0 ≤ x5 ≤ 1, 0 ≤ y5 ≤ 1, 0 ≤ 1 - x5 - y5 ≤ 1, and the thickness is 10 nm - 100 nm; the material of the P-type semiconductor transport layer (108) is Al x6 In y6 Ga 1-x6-y6 N, and the components are 0 ≤ x6 ≤ 1, 0 ≤ y6 ≤ 1, 0 ≤ 1 - x6 - y6 ≤ 1, and its thickness is 30 nm - 5 μm.

[0018] A method for fabricating a monolithic in-situ integrated light-emitting and self-driven detection device, which is used to fabricate the monolithic in-situ integrated light-emitting and self-driven detection device, and its specific steps are as follows:

[0019] A self-driven ultraviolet detector and an ultraviolet LED are sequentially grown on the substrate along the epitaxial growth direction using either molecular beam epitaxy (MBE) or metal-organic chemical vapor deposition (MOCVD).

[0020] By selectively etching portions of the UV LEDs and detectors, trapezoidal mesa surfaces are formed on the device, exposing each layer of the UV detector and UV LEDs.

[0021] The beneficial effects of this invention are as follows:

[0022] This invention discloses a monolithic in-situ integrated light emission and self-driven detection device. This invention employs Al… x Ga 1-x N / Al y Ga 1-y The N-type heterojunction structure, as a self-driven ultraviolet detector, can not only be integrated with LEDs in situ, simplifying the manufacturing process, but also fully utilizes the inherent polarization effect of III-V group nitrides to achieve self-driven detection. This not only broadens the detection wavelength range, but also completely avoids the Stokes shift problem in traditional on-chip optical chips, improving the detection capability of the on-chip system. The present invention thus solves the problems of low light-dark-current ratio and poor communication efficiency in the prior art, and has the characteristic of avoiding the Stokes shift problem. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of a monolithic in-situ integrated light emission and self-driven detection device according to the present invention.

[0024] Figure 2 This is a modeling flowchart of a monolithic in-situ integrated light emission and self-driven detection method according to the present invention.

[0025] Figure 3 This is a schematic diagram of an epitaxial wafer structure.

[0026] Figure 4 A schematic diagram of the epitaxial wafer structure after the tilted sidewalls and steps are fabricated using photolithography and etching processes.

[0027] Figure 5 A schematic diagram of the integrated device structure with tilted sidewall ultraviolet LED and self-driven ultraviolet detector obtained by vapor deposition of metal electrodes.

[0028] Figure 6 The measured emission spectrum of the deep ultraviolet LED is compared with the detection spectrum of the same multi-quantum well structure and Al. x Ga 1-x N / Al y Ga 1-y Comparison of detection spectra of N heterojunctions

[0029] In the figure, 101. Substrate, 102. Buffer layer, 103. Al x Ga 1-x N-absorbing layer, 104.Al y Ga 1-y N-layer, 105. N-type semiconductor transport layer, 106. Multiple quantum well layer, 107. P-type electron blocking layer, 108. P-type semiconductor transport layer, 109. Insulating layer, 110. Metal reflective layer, 111. First ohm electrode, 112. Second ohm electrode, 113. Third ohm electrode and 114. Fourth ohm electrode. Detailed Implementation

[0030] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0031] Example 1

[0032] like Figure 1 As shown, a monolithic in-situ integrated light-emitting and self-driven detection device includes a self-driven ultraviolet detector and an ultraviolet LED connected sequentially along the epitaxial growth direction; the self-driven ultraviolet detector is an Al x Ga 1-x N / Al y Ga 1-y N heterojunction structure.

[0033] In one specific embodiment, the self-driven ultraviolet detector specifically includes Al x Ga 1-x N-absorbing layer 103, Al y Ga 1-y N layer 104; Al y Ga 1-y The first ohmic electrode 111 is provided on the N layer 104, Al x Ga 1-x A second ohmic electrode 112 is provided on the N-absorbent layer 103.

[0034] In one specific embodiment, Al x Ga 1-x In the N-absorbing layer 103, the coefficients of each component are 0≤x≤1 and 0≤1-x≤1, and its thickness is 5nm~5μm; Al y Ga 1-y In the N-layer 104, the coefficients of each component are 0≤y≤1 and 0≤1-y≤1, and its thickness is 5nm~5μm, where x>y.

[0035] In a specific embodiment, the ultraviolet LED includes an N-type semiconductor transport layer 105, a multi-quantum well layer 106, a P-type electron blocking layer 107, a P-type semiconductor transport layer 108, and an insulating layer 109; a P-type ohmic electrode 113 is provided on the N-type semiconductor transport layer 105, and an N-type ohmic electrode 114 is provided on the P-type semiconductor transport layer 108.

[0036] In a specific embodiment, it further includes a substrate 101, a buffer layer 102, and a metal reflection layer 110;

[0037] The substrate 101, the buffer layer 102, A lx Ga 1-x N absorption layer 103, Al y Ga 1-y N layer 104, N-type semiconductor transport layer 105, multi-quantum well layer 106, P-type electron blocking layer 107, P-type semiconductor transport layer 108, insulating layer 109, and metal reflection layer 110 are arranged in sequence along the epitaxial growth direction.

[0038] In a specific embodiment, the material of the substrate 101 is sapphire, AlN, GaN, Si or SiC, and it is divided into a polar substrate and a semi-polar substrate according to the epitaxial growth direction.

[0039] In a specific embodiment, the material of the buffer layer 102 is Al x1 In y1 Ga 1-x1-y1 N, where the component coefficients are 0 ≤ x1 ≤ 1, 0 ≤ y1 ≤ 1, 0 ≤ 1 - x1 - y1 ≤ 1, and its thickness is 10 - 500 nm; in the Al x Ga 1-x N absorption layer 103, the component coefficients are 0 ≤ x ≤ 1, 0 ≤ 1 - x ≤ 1, and its thickness is 5 nm - 5 μm; in the Al y Ga 1-y N layer 104, the component coefficients are 0 ≤ y ≤ 1, 0 ≤ 1 - y ≤ 1, where x < y, and its thickness is 5 nm - 5 μm; the material of the N-type semiconductor transport layer 105 is Al x2 In y2 Ga 1-x2-y2 N, where the component coefficients are 0 ≤ x2 ≤ 1, 0 ≤ y2 ≤ 1, 0 ≤ 1 - x2 - y2 ≤ 1, and its thickness is 500 nm - 5 μm.

[0040] In a specific embodiment, the structure of the multi-quantum well layer 106 is Al x3 In y3 Ga 1-x3-y3 N / Al x4 In y4 Ga1-x4-y4 N, where the coefficients of each component are 0≤x3≤1, 0≤y3≤1, 0≤1-x3-y3≤1, 0≤x4≤1, 0≤y4≤1, 0≤1-x4-y4≤1, the band gap of the quantum barrier is greater than the band gap of the quantum well, the number of quantum wells is greater than or equal to 1, and the quantum well Al x3 In y3 Ga 1-x3-y3 The thickness of N is 1–20 nm, and the quantum barrier Al x4 In y4 Ga 1-x4-y4 The thickness of N is 5–50 nm.

[0041] In one specific embodiment, the p-type electron blocking layer 107 is made of Al. x5 In y5 Ga 1-x5-y5 N, wherein the coefficients of each component are 0≤x5≤1, 0≤y5≤1, 0≤1-x5-y5≤1, and the thickness is 10nm~100nm; the material of the P-type semiconductor transport layer 108 is Al. x6 In y6 Ga 1-x6-y6 N, with each component having the following properties: 0≤x6≤1, 0≤y6≤1, 0≤1-x6-y6≤1, and a thickness of 30nm~5μm.

[0042] In one specific embodiment, the insulating layer 109 can be made of any one of SiO2, Si3N4, and HfO2; the metal reflective layer is made of Al.

[0043] Example 2

[0044] like Figure 2 As shown, a method for fabricating a monolithic in-situ integrated light-emitting and self-driven detection device is described, the specific steps of which are as follows:

[0045] like Figure 3 As shown, a sapphire substrate, a 50 nm AlN buffer layer, and a 100 nm AlN buffer layer are sequentially constructed along the epitaxial growth direction using an organometallic chemical vapor deposition (MOCVD) system. 0.45 Ga 0.55 N-absorbing layer, 20nm Al 0.65 Ga 0.35 N-layer; the N-type semiconductor transport layer is a 5μm Al. 0.60 Ga 0.40 N layers, with an N-type doping concentration of 1×10⁻⁶. 20 cm -3 The active region consists of 5 periods of Al 0.60 Ga 0.40 N quantum barrier and Al0.45 Ga 0.55 The structure consists of N quantum wells with thicknesses of 10 nm and 3 nm, respectively, and is unintentionally doped; followed by a 20 nm thick p-Al... 0.70 Ga 0.30 The N EBL layer, the P-type semiconductor transport layer is made of 100nm Al 0.55 Ga 0.45 It consists of an N-layer and a 50nm GaN layer, with a P-type doping concentration of 1×10⁻⁶. 20 cm -3 ;

[0046] like Figure 4 As shown, the selected area is first etched to form a trapezoidal platform, exposing the Al. y Ga 1-y N-layer 104, N-type semiconductor transport layer 105 for ultraviolet LED, multiple quantum well layer 106, P-type electron blocking layer 107, P-type semiconductor transport layer 108, followed by further etching to expose Al. x Ga 1-x N-absorber layer 103; wherein the trapezoidal mesa sidewall forms a 70° angle with the horizontal direction to improve light extraction efficiency and photoelectric coupling efficiency;

[0047] like Figure 5 As shown, in this embodiment, a SiO2 passivation layer is also deposited in a specific area of ​​the surface using an atomic layer deposition method to achieve electrical isolation and passivation of defects; an Al reflector and a metal electrode are also deposited.

[0048] Example 3

[0049] More specifically, a method for fabricating a monolithic in-situ integrated light-emitting and self-driven detection device, used to fabricate the aforementioned monolithic in-situ integrated light-emitting and self-driven detection device, comprises the following specific steps:

[0050] Using a molecular beam epitaxy (MBE) device, an AlN substrate, a 100 nm AlN buffer layer, and a 200 nm AlN layer were sequentially constructed along the epitaxial growth direction. 0.50 Ga 0.50 N-absorbing layer, 10nm Al 0.80 Ga 0.20 N-layer; the N-type semiconductor transport layer is an 8μm Al. 0.65 Ga 0.35 N layers, with an N-type doping concentration of 1×10⁻⁶. 20 cm -3 The active region consists of 6 periods of Al 0.62 Ga 0.38 N quantum barrier and Al 0.49 Ga 0.51The structure consists of N quantum wells with thicknesses of 15 nm and 4 nm, respectively, and is unintentionally doped; followed by a 15 nm thick p-Al... 0.75 Ga 0.30 The N EBL layer, the P-type semiconductor transport layer is made of 500nm Al 0.58 Ga 0.42 It consists of an N-layer and a 100nm GaN layer, with a P-type doping concentration of 1×10⁻⁶. 20 cm -3 ;

[0051] First, the selected area is etched to form a trapezoidal platform, exposing the .Al y Ga 1-y N-layer 104, N-type semiconductor transport layer 105 for ultraviolet LED, multiple quantum well layer 106, P-type electron blocking layer 107, P-type semiconductor transport layer 108, followed by further etching to expose Al. x Ga 1-x N-absorber layer 103; wherein the trapezoidal mesa sidewall forms a 50° angle with the horizontal direction to improve light extraction efficiency and photoelectric coupling efficiency.

[0052] In this embodiment, as Figure 6 As shown, the present invention uses Al x Ga 1-x N / Al y Ga 1-y Compared with the measured emission spectra of deep ultraviolet LEDs as detectors, the self-driven ultraviolet detector with an N heterojunction structure has the following outstanding substantive features and significant progress: (1) Al x Ga 1-x N / Al y Ga 1-y The N heterojunction structure, as the detection region, can not only be integrated with the LED in situ and simplify the process, but also make full use of the inherent polarization effect of III-V nitrides to achieve self-driven detection; (2) The composition of the detection region is flexible and adjustable, which can not only broaden the detection wavelength range, but also completely avoid the Stokes displacement problem in traditional on-chip optical chips and improve the detection capability of the on-chip system; (3) The inclined sidewall is used to promote the transmission of photons to the substrate side, enhance the coupling efficiency, and improve the communication efficiency of the on-chip system.

[0053] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the claims of the present invention.

Claims

1. A monolithic in-situ integrated light emission and self-driven detection device, characterized in that: It includes a self-driven ultraviolet detector and an ultraviolet LED connected sequentially along the epitaxial growth direction; the self-driven ultraviolet detector is an Al x Ga 1-x N / Al y Ga 1-y N-heterojunction structure; The self-driven ultraviolet detector specifically includes Al x Ga 1-x N-absorbing layer (103) and Al y Ga 1-y N layer (104); Al y Ga 1- y The first ohmic electrode (111) is provided on the N layer (104), Al x Ga 1-x A second ohmic electrode (112) is provided on the N-absorbing layer (103); Al x Ga 1-x In the N-absorbing layer (103), the coefficients of each component are 0≤x≤1, 0≤1-x≤1, and its thickness is 5 nm~5 μm; Al y Ga 1-y In layer N (104), the coefficients of each component are 0≤y≤1, 0≤1-y≤1, and its thickness is 5 nm~5 μm, where x> y; The ultraviolet LED comprises an N-type semiconductor transport layer (105), a multiple quantum well layer (106), a P-type electron blocking layer (107), a P-type semiconductor transport layer (108), and an insulating layer (109); the material of the N-type semiconductor transport layer (105) is Al. x2 In y2 Ga 1-x2-y2 N, where the coefficients of each component are 0≤x2≤1, 0≤y2≤1, and 0≤1-x2-y2≤1; the structure of the multi-quantum well layer (106) is Al. x3 In y3 Ga 1-x3-y3 N / Al x4 In y4 Ga 1-x4-y4 N, where the coefficients of each component are 0≤x3≤1, 0≤y3≤1, 0≤1-x3-y3≤1, 0≤x4≤1, 0≤y4≤1, 0≤1-x4-y4≤1; the material of the P-type electron blocking layer (107) is Al. x5 In y5 Ga 1-x5-y5 N, where the coefficients of each component are 0≤x5≤1, 0≤y5≤1, and 0≤1-x5-y5≤1; the material of the P-type semiconductor transport layer (108) is Al. x6 In y6 Ga 1-x6-y6 N, each component is 0≤x6≤1, 0≤y6≤1, 0≤1-x6-y6≤1; P-type ohmic electrodes (113) are provided on the N-type semiconductor transport layer (105), and N-type ohmic electrodes (114) are provided on the P-type semiconductor transport layer (108).

2. The monolithic in-situ integrated light emission and self-driven detection device according to claim 1, characterized in that: It also includes a substrate (101), a buffer layer (102), and a metal reflective layer (110). Substrate (101), buffer layer (102), Al x Ga 1-x N-absorbing layer (103), Al y Ga 1-y The N-layer (104), N-type semiconductor transport layer (105), multiple quantum well layer (106), P-type electron blocking layer (107), P-type semiconductor transport layer (108), insulating layer (109), and metal reflective layer (110) are arranged sequentially along the epitaxial growth direction.

3. The monolithic in-situ integrated light emission and self-driven detection device according to claim 2, characterized in that: The substrate (101) is made of sapphire, AlN, GaN, Si or SiC, and is classified as polar substrate or semi-polar substrate according to the epitaxial growth direction.

4. The monolithic in-situ integrated light emission and self-driven detection device according to claim 3, characterized in that: The buffer layer (102) is made of Al. x1 In y1 Ga 1-x1-y1 N, wherein the coefficients of each component are 0≤x1≤1, 0≤y1≤1, 0≤1-x1-y1≤1, and their thickness is 10~500 nm; the thickness of the N-type semiconductor transport layer (105) is 500 nm~5μm.

5. The monolithic in-situ integrated light emission and self-driven detection device according to claim 4, characterized in that: The band gap of the quantum barrier in the multi-quantum-well layer (106) is greater than the band gap of the quantum well, and the number of quantum wells is greater than or equal to 1. x3 In y3 Ga 1-x3-y3 The thickness of N is 1–20 nm, and the quantum barrier Al x4 In y4 Ga 1-x4-y4 The thickness of N is 5–50 nm.

6. The monolithic in-situ integrated light emission and self-driven detection device according to claim 4, characterized in that: The thickness of the P-type electron blocking layer (107) is 10 nm to 100 nm; the thickness of the P-type semiconductor transport layer (108) is 30 nm to 5 μm.

7. A method for fabricating a monolithic in-situ integrated light-emitting and self-driven detection device, characterized in that: The specific steps for fabricating the monolithic in-situ integrated light emission and self-driven detection device as described in any one of claims 1 to 6 are as follows: A self-driven ultraviolet detector and an ultraviolet LED are sequentially grown on the substrate along the epitaxial growth direction using either molecular beam epitaxy (MBE) or metal-organic chemical vapor deposition (MOCVD). By selectively etching portions of the UV LEDs and detectors, trapezoidal mesa surfaces are formed on the device, exposing each layer of the UV detector and UV LEDs.

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