CN-116314394-B - Photoelectric detector and preparation method thereof

CN116314394BCN 116314394 BCN116314394 BCN 116314394BCN-116314394-B

Abstract

The invention provides a photoelectric detector and a preparation method thereof, relating to the fields of photoelectric detection device research and photoelectron materials, comprising a substrate, a first buffer layer, a second buffer layer, a first ohmic contact layer, an absorption layer, an electronic barrier layer and a second ohmic contact layer which are sequentially stacked on the substrate; the first buffer layer is composed of In x Al 1‑x As with gradually changed In composition, the second buffer layer is composed of a plurality of groups of In y Al 1‑y As layers and In y Ga 1‑y As layers which are alternately laminated and grown In a periodic mode, and the electronic barrier layer is made of AlGaAsSb. The method reduces dislocation density caused by larger lattice mismatch between the high In component absorption layer and the substrate, reduces defects In the absorption layer, improves crystallization quality of the absorption layer, and simultaneously adopts AlGaAsSb as an electron barrier layer to effectively improve transport and collection efficiency of photo-generated carriers.

Inventors

ZHENG WANHUA
CAO PENG
PENG HONGLING
WANG TIANCAI

Assignees

中国科学院半导体研究所

Dates

Publication Date: 20260512
Application Date: 20230317

Claims (6)

1. A photoelectric detector, which comprises a light source, a light source and a light receiving element, characterized by comprising the following steps: a substrate (1), a first buffer layer (2), a second buffer layer (3), a first ohmic contact layer (4), an absorption layer (5), an electron barrier layer (6) and a second ohmic contact layer (7) which are sequentially stacked on the substrate (1); The first buffer layer (2) is composed of In x Al 1-x As with gradually changed In composition, the second buffer layer (3) is composed of a plurality of groups of In y Al 1-y As layers and In y Ga 1-y As layers which are alternately laminated and grown In a periodic manner, and the electronic barrier layer (6) is made of AlGaAsSb; the In component of the first buffer layer (2) increases gradually along the direction of the second buffer layer (3) pointing to the substrate (1), and the In component of the first buffer layer (2) increases from 0.53 to 0.8, namely 0.53< x is less than or equal to 0.8; the thickness of the first buffer layer (2) is 30-50 nm, the doping source of the first buffer layer (2) is Te, and the doping concentration is 1 multiplied by 10 16 cm -3 ~1×10 17 cm -3 ; The second buffer layer (3) is formed by alternately laminating 30 groups of In y Al 1-y As layers and In y Ga 1-y As layers which are grown In a periodic manner, wherein y is more than or equal to 0.75 and less than or equal to 0.85, the thicknesses of the In y Al 1-y As layers and the In y Ga 1-y As layers are 10-15 nm, the total thickness of the second buffer layer (3) is 600-900 nm, the doping source of the second buffer layer (3) is Te, and the doping concentration is 5 multiplied by 10 16 cm -3 ~1×10 17 cm -3 ; The absorption layer (5) is made of In 0.8 Ga 0.2 As, the thickness of the absorption layer (5) is 2-2.5 mu m, and the absorption layer (5) adopts an unintended doping mode.
2. The photodetector according to claim 1, wherein the first ohmic contact layer (4) is made of In 0.8 Al 0.2 As, the thickness of the first ohmic contact layer (4) is 150-200 nm, the doping source of the first ohmic contact layer (4) is Te, and the doping concentration is 5 x 10 18 cm -3 ~1×10 19 cm -3 .
3. The photodetector according to claim 1, wherein the electron barrier layer (6) has a thickness of 50-100 nm, and the electron barrier layer (6) is unintentionally doped.
4. The photodetector according to claim 1, wherein the second ohmic contact layer (7) is made of In 0.8 Al 0.2 As, the thickness of the second ohmic contact layer (7) is 150-200 nm, the doping source of the second ohmic contact layer (7) is Te or Be, and the doping concentration is 1x 10 18 cm -3 ~1×10 19 cm -3 .
5. The photodetector according to claim 1, characterized in that the substrate (1) is made of GaSb, the thickness of the substrate (1) being 50 μm.
6. A method of manufacturing a photodetector according to any one of claims 1 to 5, comprising: a first buffer layer (2), a second buffer layer (3), a first ohmic contact layer (4), an absorption layer (5), an electron barrier layer (6) and a second ohmic contact layer (7) are sequentially stacked on a substrate (1); The first buffer layer (2) is composed of In x Al 1-x As with gradually changed In composition, the second buffer layer (3) is composed of a plurality of groups of In y Al 1-y As layers and In y Ga 1-y As layers which are alternately laminated and grown In a periodic mode, and the electronic barrier layer (6) is made of AlGaAsSb.

Description

Photoelectric detector and preparation method thereof Technical Field The disclosure relates to the technical field of photoelectric detection device research and optoelectronic materials, in particular to a photoelectric detector and a preparation method thereof. Background The near infrared expansion wave band (2-3 μm) contains various atmospheric gas absorption windows, and has important significance for various purposes including gas detection, space remote sensing, imaging and the like. The detector based on InGaAs material as the absorption layer has the characteristics of large material light absorption coefficient, high quantum efficiency, good room temperature working effect, low noise and the like. However, the cut-off response wavelength of the In 0.53Ga0.47 As material matched with the InP substrate is only about 1.7 μm, and effective detection of the short-wave infrared expansion wavelength band cannot be realized. By increasing the proportion of the In component x In the In xGa1-x As, the detection of the InGaAs-based photoelectric detector at the near infrared expansion wavelength (2-3 μm) can be realized. However, increasing the In composition tends to produce a larger lattice mismatch between the absorber layer and the substrate, thereby forming a larger dislocation density In the growth process, leading to an increase In defects In the absorber layer and lower transport and collection efficiency of photogenerated carriers In the operating state, affecting the dark current characteristics and light response characteristics of the final device. Disclosure of Invention In view of the foregoing, the present disclosure provides a photodetector and a method of manufacturing the same to improve the dislocation density problem caused by lattice mismatch. One aspect of the disclosure provides a photodetector, which comprises a substrate, a first buffer layer, a second buffer layer, a first ohmic contact layer, an absorption layer, an electronic barrier layer and a second ohmic contact layer which are sequentially stacked on the substrate, wherein the first buffer layer is composed of In xAl1-x As with gradually changed In composition, the second buffer layer is composed of a plurality of groups of In yAl1-y As layers and In yGa1-y As layers which are alternately stacked and grown In a periodic manner, and the electronic barrier layer is made of A1 GaAsSb. According to the embodiment of the disclosure, the In composition of the first buffer layer increases gradually along the direction of the second buffer layer pointing to the substrate, and the In composition of the first buffer layer increases from 0.53 to 0.8, that is, 0.53< x≤0.8. According to the embodiment of the disclosure, the thickness of the first buffer layer is 30-50 nm, the doping source of the first buffer layer is Te, and the doping concentration is 1×10 16cm-3～1×1017cm-3. According to the embodiment of the disclosure, the second buffer layer is formed by alternately stacking 30 groups of In yAl1-y As layers and In yGa1-y As layers which are grown In a periodic manner, wherein y is more than or equal to 0.75 and less than or equal to 0.85, the thicknesses of the In VAl1-y As layers and the In yGa1-y As layers are 10-15 nm, the total thickness of the second buffer layer is 600-900 nm, the doping source of the second buffer layer is Te, and the doping concentration of the second buffer layer is 5 multiplied by 10 16cm-3～1×1017cm-3. According to the embodiment of the disclosure, the first ohmic contact layer is made of In 0.8Al0.2 As, the thickness of the first ohmic contact layer is 150-200 nm, the doping source of the first ohmic contact layer is Te, and the doping concentration is 5×10 18cm-3～1×1019cm-3. According to the embodiment of the disclosure, the absorption layer is made of In 0.8Ga0.2 As, the thickness of the absorption layer is 2-2.5 mu m, and the absorption layer adopts an unintended doping mode. According to the embodiment of the disclosure, the thickness of the electron barrier layer is 50-100 nm, and the electron barrier layer adopts an unintentional doping mode. According to the embodiment of the disclosure, the second ohmic contact layer is made of In 0.8Al0.2 As, the thickness of the second ohmic contact layer is 150-200 nm, the doping source of the second ohmic contact layer is Te or Be, and the doping concentration is 1×10 18cm-3～1×1019cm-3. According to the embodiment of the disclosure, the substrate is made of GaSb, and the thickness of the substrate is 50 microns. The embodiment of the disclosure also discloses a preparation method of the photoelectric detector, which is used for preparing the photoelectric detector and comprises the steps of sequentially stacking a first buffer layer, a second buffer layer, a first ohmic contact layer, an absorption layer, an electronic barrier layer and a second ohmic contact layer on a substrate, wherein the first buffer layer is composed of In xAl1-x As with gradually change