Two-color detector and preparation method thereof

Abstract

The invention discloses a double-color photoelectric detector and a preparation method thereof, and belongs to the technical field of photoelectric detectors, and the preparation method of the double-color photoelectric detector comprises the steps: preparing a P-type infrared light absorption material on an N-type silicon substrate; preparing an N-type wide band gap material on the P-type infrared light absorption material; and electrodes are plated on the N-type silicon wafer and the N-type wide-band gap material and are respectively led out. According to the structure of the device, a heterojunction formed by an NPN type, N type silicon and a P type infrared light absorption material detects the wave band of 400-1100 nm, a heterojunction formed by the P type infrared light absorption material and an N type wide band gap material detects the wave band of 1100-5000 nm, and the prepared NPN device achieves two-color detection of 400-1100 nm and 1100-5000 nm through positive and negative bias regulation and control. Compared with a traditional mechanically-connected double-color detector structure, the visible-infrared double-color detector which is high in integration level, excellent in performance, simple in process and low in cost can be prepared.

Description

Technical Field

[0001] The invention discloses a dual-color detector and a preparation method thereof, belonging to the technical field of photoelectric detectors. Background Art

[0002] Photoelectric detectors are devices that can convert optical signals into electrical signals for output. They are widely used in defense, industry, people's livelihood and other fields. The development of modern photoelectric detection devices and imaging systems often requires multi-band operation, which can save space occupied by military and civilian equipment, reduce external targets, and facilitate the installation and debugging of the system. In terms of imaging guidance equipment, the development of single-band imaging technology from units to linear arrays and focal plane arrays has been relatively complete internationally, but due to the large differences in the characteristics of targets in different spectral bands, single-band systems have great deficiencies in obtaining information, such as the high false alarm rate of the warning system. In high-tech confrontations, reconnaissance and guidance behaviors have or will soon develop from a single working mode to a composite working mode through technical means such as multi-mode compounding, multi-spectrum fusion, and active and passive combination, so as to achieve simultaneous search, tracking and sighting of targets in multiple bands such as visible light and infrared.

[0003] In the field of photoelectric detection and imaging technology, silicon-based photodetectors have the advantages of abundant raw materials, mature manufacturing processes, and low costs. Therefore, silicon-based photodetectors are considered to be one of the key development directions in the future. In recent years, in addition to the trends of focal plane, large array, and miniaturization, the development of silicon-based photodetectors has also become an inevitable trend of dual-colorization. At present, the common materials integrated with silicon photodetectors are mainly III-V compound semiconductors such as indium gallium arsenide (InGaAs) and indium antimonide (InSb). Depending on the different bandgap widths of the materials, the detection band covers the visible-short-wave infrared and visible-mid-infrared bands. These existing III-V compound detectors have good photoelectric properties and high sensitivity, but due to their high price, poor thermomechanical properties, poor crystal quality, and incompatibility with silicon-based CMOS processes, their application in large-scale dual-color detectors composed of silicon photodetectors is limited. Patent CN 220710333 U discloses stacking silicon photodiodes and InGaAs photodiodes together to achieve visible-near infrared detection ( Figure 1 ), but the photoelectric detectors are interconnected by mechanical connection, and the stability and reliability cannot be guaranteed. In addition, the circuit design of the two detection modules needs to be carried out separately, the preparation process is complicated, the package size is large, and the cost is high.

[0004] In view of the problems of complex preparation process, cumbersome circuit design, large package size, and being unfavorable for device integration and miniaturization caused by the mechanical integration of silicon photodetectors and III-V semiconductor photodetectors in the existing two-color detection technology, the purpose of the present invention is to provide a new two-color detector and a preparation method to achieve visible-infrared two-color detection with high integration, excellent performance, simple process and low cost. Summary of the invention

[0005] The present invention provides a two-color detector and a method for preparing the same, the method comprising the following steps:

[0006] Step 1: Prepare a P-type infrared absorbing material on an N-type silicon substrate;

[0007] Step 2: preparing an N-type wide bandgap material on a P-type infrared absorbing material;

[0008] Step 3: Electrodes are plated on the N-type silicon wafer and the N-type wide bandgap material and are led out respectively;

[0009] Furthermore, the thickness of the N-type silicon substrate in step 1 is 150-200 μm, the resistivity is 1-10 Ω·cm, and the P-type infrared absorbing material is selected from lead salt materials such as PbSe, PbTe, PbS, etc., and a 500-1000 nm thin film is prepared at room temperature by sputtering or evaporation technology, so that the N-type silicon is depleted;

[0010] Furthermore, the N-type wide bandgap material in step 2 is selected from ZnO, CdS and other materials, and a 100-200 nm thin film is prepared at room temperature by sputtering or evaporation technology, so that the P-type material is depleted;

[0011] Furthermore, the electrodes plated in step 3 are Ag, Al and other electrodes on the silicon side, and Au, Ni and other electrodes on the P-type infrared absorbing material side. The electrodes are led out after the electrode plating is completed.

[0012] In summary, the present invention provides a new dual-color detector and preparation method, the device structure is NPN type, the heterojunction composed of N-type silicon and P-type infrared light absorbing material detects the band of 400-1100nm, and the heterojunction composed of P-type infrared light absorbing material and N-type wide bandgap material detects the band of 1100-5000nm, and the dual-color detection of 400-1100nm and 1100-5000nm is achieved by positive and negative bias control. Compared with the traditional mechanically connected dual-color detector structure, the present invention can realize a visible-infrared dual-color detector with high integration, excellent performance, simple process and low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a device that interconnects traditional silicon photodiodes and III-V semiconductor photodiodes

[0014] In the figure: 11, silicon photodiode; 12, electrode lead; 21, III-V semiconductor photodiode; 22, electrode lead

[0015] Figure 2 The silicon-based NPN device structure of the present invention is

[0016] In the figure: 11, N-type silicon; 12, electrode lead; 21, P-type infrared light absorbing material; 31, N-type wide bandgap material; 32, electrode lead DETAILED DESCRIPTION

[0017] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0018] A two-color detector (such as Figure 2 As shown) and a preparation method thereof, the method comprises the following steps:

[0019] Step 1: Prepare a P-type infrared light-absorbing material on an N-type silicon substrate. The N-type silicon substrate has a thickness of 150 to 200 μm and a resistivity of 1 to 10 Ω·cm. The P-type infrared light-absorbing material is a lead salt material such as PbSe, PbTe, PbS, etc., and a 500 to 1000 nm thin film is prepared at room temperature by sputtering or evaporation technology, so that the N-type silicon is depleted;

[0020] Step 2: Prepare an N-type wide bandgap material on the P-type infrared absorbing material. The N-type wide bandgap material is selected from ZnO, CdS and other materials, and a 100-200nm thin film is prepared at room temperature by sputtering or evaporation technology, so that the P-type material is depleted;

[0021] Step 3: Electrodes are plated on the N-type silicon wafer and the N-type wide bandgap material and led out respectively. The electrodes are Ag, Al, etc. electrodes on the silicon side and Au, Ni, etc. electrodes on the P-type infrared absorbing material side. The electrodes are led out after the electrode plating is completed.

[0022] Example 1

[0023] A two-color detector and a preparation method thereof, the method comprising the following steps:

[0024] (1) Select N-type silicon wafer with a resistivity of 1-10Ω·cm and a thickness of 300-500μm;

[0025] (2) Using magnetron sputtering technology to prepare 500nm PbTe film on N-type silicon wafer;

[0026] (3) Prepare a 200 nm CdS film on a PbTe film by evaporation;

[0027] (4) A 300 nm thick Ag interdigital electrode was plated on the N-type silicon side, and then a 50 nm thick gold electrode was plated on the PbTe side.

[0028] This specific embodiment is merely an explanation of the present invention and is not a limitation of the present invention. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed. However, as long as they are within the scope of the claims of the present invention, they are protected by the patent law.

Claims

1. A two-color detector and a method for preparing the same, the method comprising the following steps: Step 1: Prepare a P-type infrared absorbing material on an N-type silicon substrate; Step 2: preparing an N-type wide bandgap material on a P-type infrared absorbing material; Step 3: Electrodes are plated on the N-type silicon wafer and the N-type wide bandgap material and are led out separately.

2. The P-type infrared light absorbing material according to claim 1, characterized in that: The P-type infrared absorbing material in step 1 is selected from lead salt materials such as PbSe, PbTe, PbS, etc., and is prepared at room temperature by sputtering or evaporation technology, so that the N-type silicon is depleted.

3. The N-type wide bandgap material according to claim 1, characterized in that: The N-type wide bandgap material in step 2 is selected from materials such as ZnO and CdS, and is prepared at room temperature by sputtering or evaporation technology, so that the P-type material is depleted.

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