CN-119342940-B - Tellurium-cadmium-mercury double-layer component heterojunction infrared detector and preparation method thereof

CN119342940BCN 119342940 BCN119342940 BCN 119342940BCN-119342940-B

Abstract

The invention discloses a tellurium-cadmium-mercury double-layer component heterojunction detector which comprises a substrate material layer, an n-type absorption layer, a surface n-type wide forbidden band heterogeneous layer, a passivation layer and a contact electrode layer which are arranged in a stacked mode, wherein the surface n-type wide forbidden band heterogeneous layer is a wide forbidden band heterogeneous layer prepared on the surface of the n-type absorption layer based on a mercury-rich vertical liquid phase epitaxy technology, the rest impurities are n-type, the passivation layer covers at least part of areas of an isolation region and a p-type injection region in a forward projection direction, the part of the passivation layer, which does not cover the p-type injection region, is a contact hole, and the contact electrode layer is in contact with the p-type injection region, and the forward projection area of the contact electrode is larger than and covers the contact hole. The invention realizes interface interdiffusion by utilizing the growth process of the n-type wide bandgap heterogeneous layer, and realizes the mercury cadmium telluride p-on-n plane heterojunction device by As ion implantation. The invention can effectively inhibit tunneling current and surface electric leakage, reduce dark current and improve device performance.

Inventors

ZHANG YANG
YANG JIN
SONG LINWEI
QIN GANG
CONG SHUREN
Xia Shanjiao
KONG JINCHENG
WANG WENJIN
HUANG YU
LI DA
DENG WENBIN
CHEN PAN
ZHAO GUIQIN
WANG XUESONG

Assignees

昆明物理研究所

Dates

Publication Date: 20260512
Application Date: 20241011

Claims (10)

1. The tellurium-cadmium-mercury double-layer component heterojunction infrared detector is characterized by comprising a substrate material layer, an n-type absorption layer, an n-type wide forbidden band heterogeneous layer, a passivation layer and a contact electrode layer which are arranged in a stacked mode; The n-type wide band gap heterogeneous layer is made of residual impurity n-type materials, is prepared on the surface of the n-type absorption layer by adopting a mercury-rich vertical liquid phase epitaxy process, and has residual impurities controlled within 8E13/cm 3 ; The contact electrode layer is contacted with the p-type injection region, and the orthographic projection area of the contact electrode is larger than and covers the contact hole; after the n-type wide band gap heterogeneous layer grows, forming an array P-type injection region through photoetching, selectively injecting As impurities into the n-type wide band gap heterogeneous layer, and forming an independent pixel of a P-on-n structure after annealing activation; The tellurium-cadmium-mercury double-layer component heterojunction is used for inhibiting tunneling current and surface electric leakage and reducing dark current.
2. The mercury cadmium telluride double layer component heterojunction infrared detector of claim 1, wherein: The material of the substrate layer is selected from one of Cd 1-x Zn x Te and Si-based substituted substrate, wherein the value of x is less than 0.5.
3. The mercury cadmium telluride double layer component heterojunction infrared detector of claim 1, wherein: The n-type absorption layer and the n-type wide forbidden band heterogeneous layer are made of Hg 1-x Cd x Te, wherein the value of x is less than or equal to 0.6.
4. A mercury cadmium telluride double layer component heterojunction infrared detector as claimed in claim 3, wherein: the x value in Hg 1-x Cd x Te of the n-type absorption layer is 0.1 to 0.4.
5. A mercury cadmium telluride double layer component heterojunction infrared detector as claimed in claim 3, wherein: The x value in the Hg 1-x Cd x Te material of the n-type wide bandgap heterogeneous layer is 0.23 to 0.6.
6. The mercury cadmium telluride double layer component heterojunction infrared detector of any one of claims 1-5, wherein: The passivation layer thickness ranges from 500 angstroms to 20000 angstroms.
7. The mercury cadmium telluride double layer component heterojunction infrared detector of any one of claims 1-5, wherein: the passivation layer material comprises any one or a combination of materials of CdTe, znS, siN and BN.
8. A method for preparing a mercury cadmium telluride double-layer component heterojunction infrared detector as defined in any one of claims 1 to 7, wherein the method comprises the following steps: Growing an n-type absorption layer on the substrate material layer; performing secondary growth on the n-type absorption layer, and preparing an n-type wide forbidden band heterogeneous layer by adopting a mercury-rich vertical liquid phase epitaxy technology; Photoetching is carried out on the surface of the n-type wide forbidden band heterogeneous layer, an injection region and an isolation region protected by photoresist are formed after development, and the injection region is leaked; ion implantation is carried out by using As ions after photoetching, photoresist is removed after implantation, activation annealing is carried out, a P region is formed, and independent pixels are formed by separation of isolation regions; growing a passivation layer on the surface of the n-type wide forbidden band heterogeneous layer through a magnetron sputtering process, a thermal evaporation process or an MBE process; Photoetching the surface of the passivation layer, removing the passivation layer outside the photoresist protection area by adopting an etching or corrosion process, preparing a contact hole and stripping photoresist; photoetching is carried out on the pixel area, and after development, the area except the contact electrode is protected; Preparing a metal layer of the contact electrode by using a thermal evaporation process; and immersing the material into stripping liquid, and removing photoresist and a surface metal layer on the surface of the material in the protection area through a stripping process to obtain the tellurium-cadmium-mercury double-layer component heterojunction infrared detector.
9. The method for preparing the tellurium-cadmium-mercury double-layer component heterojunction planar junction infrared detector as set forth in claim 7, wherein the dark current level of the tellurium-cadmium-mercury double-layer component heterojunction planar junction infrared detector reaches Rule22 dark current empirical formula at low temperature.
10. The method for preparing the tellurium-cadmium-mercury double-layer component heterojunction planar junction infrared detector as set forth in claim 9, wherein the response wavelength of the tellurium-cadmium-mercury double-layer component heterojunction planar junction infrared detector is up to 13.3 microns at 77K.

Description

Tellurium-cadmium-mercury double-layer component heterojunction infrared detector and preparation method thereof Technical Field The invention belongs to the technical field of mercury-cadmium-tellurium infrared detectors, and particularly relates to a P-on-n-type mercury-cadmium-tellurium double-layer component heterojunction detector based on a mercury-rich vertical liquid phase epitaxy technology and a preparation method thereof. Background Infrared focal plane detectors have been used in a number of military, industrial, environmental, medical, etc. applications. Among the infrared detection materials, the tellurium-cadmium-mercury material has the advantage of high quantum efficiency, the component x is changed, the forbidden band width of the tellurium-cadmium-mercury material meets the infrared detection of three atmospheric windows of 1-3 mu m, 3-5 mu m and 8-14 mu m, the tellurium-cadmium-mercury material has the advantage of high quantum efficiency, and the advantages are obvious in the aspect of basic physical properties. Tellurium-cadmium-mercury infrared focal plane detectors have been developed to the third generation, and the main characteristics include large area arrays, very long waves, polychromatic devices, HOT devices and the like, and are dominant in the field of high-end infrared detection. The technical route of the tellurium-cadmium-mercury infrared detector mainly comprises an N-on-P structure and a P-on-N structure, in the current mature device technology, the quantum efficiency of the infrared detector is over 80 percent and even reaches 100 percent, the potential of greatly improving the device performance is not large from the angle of optical signals, and compared with the potential of greatly improving the performance of the tellurium-cadmium-mercury infrared detector by several orders of magnitude through reducing dark current. In the two structures, the P-on-n type infrared detector has obvious advantages in the aspect of reducing dark current, and the reduction amplitude reaches 2 orders of magnitude. The P-on-n technology route includes planar homojunctions (implant into junctions) and mesa heterojunctions (growth into junctions). According to the mesa heterojunction technical route, the tellurium-cadmium-mercury material is doped with In-situ As, the activation rate is high, the n-type tellurium-cadmium-mercury material doped with In element is firstly grown on the substrate material In a liquid phase epitaxy mode, the p-type tellurium-cadmium-mercury material doped with As element is further grown, and a pn junction is formed after the growth through proper activation annealing. The n-type layer is an absorption layer with the thickness of more than 5 mu m, the p-type layer is thinner and is generally within 2 mu m, the Cd component content of the p-type layer is higher than that of the n-type layer, the forbidden bandwidth is larger, the material is more stable, the tunneling current and noise can be reduced, and the low-temperature performance of the material is better than that of a homojunction. In a mesa heterojunction process route, the tellurium-cadmium-mercury area array detector needs to isolate adjacent pixel pn junctions, an etching/corrosion process is generally adopted to isolate a p-type layer of each pixel, damage to tellurium-cadmium-mercury materials in a mesa preparation process is difficult to avoid, a large number of free surfaces of side walls are introduced in the process, fine passivation treatment is needed to be carried out on the surfaces in a subsequent process, compared with a plane junction route, the coverage and interface compactness of the side wall passivation layers are poor compared with the plane junction route, passivation difficulty is higher, and uniformity of mesa preparation is difficult to control. In-doped n-type tellurium-cadmium-mercury material grows on a substrate material In a liquid phase epitaxy mode In a plane homojunction process route, a P region is prepared by adopting an As implantation process, and the tellurium-cadmium-mercury material after As ion implantation can form a pn junction only by being activated by a high-temperature annealing process. The planar homojunction heterojunction process route cannot realize surface energy band modulation structurally, the defect density of an injection region is high, a complex annealing process is needed in the later period, the defect density of the injection region is reduced, the process difficulty is high, and dark current is easily increased due to residual defects. In order to avoid the problem of high surface passivation difficulty in the planar homojunction process, a planar heterojunction process is developed, a MBE technology is adopted to prepare a double-layer component heterogeneous material, a high-resistance layer exists on the surface, an As ion implantation process is adopted to prepare a P-on-n structure, and the device process is the same As the planar h