CN-121976155-A - Electron beam evaporation method of cadmium telluride film

Abstract

The invention belongs to the field of semiconductor materials and devices, and particularly relates to an electron beam evaporation method of a cadmium telluride film. The method comprises the steps of controlling the vapor deposition rate by controlling the spot size and scanning speed of the electron beam, and comparing passivation effects of cadmium telluride on mercury cadmium telluride at different vapor deposition rates. The method solves the technical problem that the rate of growing the cadmium telluride film by the electron beam is difficult to control in the prior art, and the scheme realizes high-quality passivation of the mercury cadmium telluride film. For materials with low thermal conductivity, the method is applicable to electron beam evaporation.

Inventors

• CHEN YAN
• Tai Xiaochi
• WANG XUDONG
• TONG JINCHAO
• WANG JIANLU
• CHU JUNHAO

Assignees

• 复旦大学

Dates

Publication Date

20260505

Application Date

20251223

Claims (6)

1. 1. An electron beam evaporation method of a cadmium telluride film is characterized by comprising the following specific steps: (1) Fixing a mercury cadmium telluride substrate on a sample stage; (2) Adding the cadmium telluride bulk evaporation material into a crucible; (3) Arranging a sample table and a crucible in a cavity, and vacuumizing the cavity to a vacuum degree of 1.7E-7 Pa; (4) The electron beam is used for bombarding the cadmium telluride block-shaped evaporation material, vapor deposition is started, and the vapor deposition rate is 0.2A/s-10A/s; (5) And after the evaporation is finished, breaking vacuum to obtain the cadmium telluride film taking mercury cadmium telluride as a substrate.
2. 2. The method of electron beam evaporation of a cadmium telluride thin film according to claim 1, wherein in step (4), the scattered spot size gain is 20-120.
3. 3. The method of electron beam evaporation of a cadmium telluride film according to claim 2, wherein in step (4), the scattered light spot is scanned at a pattern speed of 80-140 Hz.
4. 4. The method of electron beam evaporation of a cadmium telluride film according to claim 3 wherein in step (4), the rotation speed of the scattered light spot pattern is 0-50 Hz.
5. 5. The method of electron beam evaporation according to any of claims 1 to 4, wherein the passivation of mercury cadmium telluride is achieved, the density of the fixed charge after passivation is reduced to 1.138×10 11 cm -2 , the density of the slow interface state is reduced to 1.067×10 11 cm -2 , and the density of the minimum fast interface state is reduced to 2.807 ×10 10 cm -2 eV -1 .
6. 6. The application of the cadmium telluride thin film in the fields of semiconductors, photoelectric detection and solar cells.

Description

Electron beam evaporation method of cadmium telluride film Technical Field The invention belongs to the field of semiconductor materials and devices, and particularly relates to an electron beam evaporation method of a cadmium telluride film. Background The cadmium telluride thin film can be realized by thermal evaporation, electron beam evaporation, magnetron sputtering, hot wall epitaxy, molecular Beam Epitaxy (MBE), metal Organic Chemical Vapor Deposition (MOCVD), electrochemical deposition and the like. The cadmium telluride film has the advantages of lattice constant matching with the mercury cadmium telluride material, wide forbidden bandwidth, surface leakage inhibition and the like, and is a better choice for the surface passivation of mercury cadmium telluride. Most of the prior art grows cadmium telluride films by thermal evaporation, and many of the prior art grows by MBE, but the prior art is not suitable for mass production due to the characteristics of expensive MBE equipment, difficult maintenance and the like. The passivation layer has better compactness in theory by improving the power of magnetron sputtering, but the surface damage of tellurium, cadmium and mercury can be brought, so that the interface of the material is inverted, and the performance of the infrared device is seriously affected. Electron Beam Evaporation (EBE) provides a low damage, cost effective alternative, and previous work has investigated the morphology and composition of EBE deposited cadmium telluride. Further research in aspects such as system process optimization and electrical effects has not been carried out. Therefore, it is necessary to provide an electron beam evaporation method of the cadmium telluride thin film to realize high-quality passivation of mercury cadmium telluride. Disclosure of Invention The invention aims to provide an electron beam evaporation method of a cadmium telluride film with low growth cost and small substrate damage. The electron beam evaporation method of the cadmium telluride thin film controls the evaporation rate by controlling the spot size and the scanning speed of the electron beam, and compares the passivation effect of cadmium telluride on mercury cadmium telluride with different evaporation rates; the method comprises the following specific steps: (1) Fixing a mercury cadmium telluride substrate on a sample stage; (2) Adding the cadmium telluride bulk evaporation material into a crucible; (3) Arranging a sample table and a crucible in a cavity, and vacuumizing the cavity to a vacuum degree of 1.7E-7 Pa; (4) The electron beam is used for bombarding the cadmium telluride block-shaped evaporation material, vapor deposition is started, and the vapor deposition rate is 0.2A/s-10A/s; (5) And after the evaporation is finished, breaking vacuum to obtain the cadmium telluride film taking mercury cadmium telluride as a substrate. Further, in the step (4), the gain of the scattered light spot size is 20-120. Further, in the step (4), the scanning speed of the scattered light spot is 80-140 Hz. Further, in the step (4), the rotation speed of the scattered light spot pattern is 0-50 Hz. In the invention, a zinc sulfide film is evaporated by the same method, and cadmium telluride and the zinc sulfide film are sequentially deposited on a mercury cadmium telluride substrate, wherein the evaporation rate is 0.5A/s. The cadmium telluride film obtained by the preparation method can be used for passivation of mercury cadmium telluride, the fixed charge density after passivation is reduced to 1.138 multiplied by 10 11 cm-2, the slow interface state density is reduced to 1.067 multiplied by 10 11 cm-2, and the minimum fast interface state density is reduced to 2.807 multiplied by 10 10 cm-2eV-1. The interface state density of about 10 12 is obviously improved compared with that achieved by other passivation schemes. In the invention, the cadmium telluride thin film is applied to the fields of semiconductors, photoelectric detection and solar cells. The invention solves the technical problem that the rate of growing the cadmium telluride film by the electron beam is difficult to control in the prior art, realizes high-quality passivation of mercury cadmium telluride, and is suitable for all low-thermal-conductivity materials which use electron beam evaporation and evaporation. According to the invention, the wafer-level tellurium film is grown through electron beam evaporation, and then the crystallinity of the tellurium film is improved through heat treatment in inert gas, so that the mobility and the piezoelectric coefficient are improved, and the method has the following specific advantages: (1) The stable growth of the cadmium telluride thin film at different rates is realized by controlling the shape, the size, the speed and the like of the electron beam light spot, so that the growth of the high-quality cadmium telluride thin film is realized; (2) The evaporation method is also applicable t