Method for analyzing defect source of tellurium-cadmium-mercury film

Abstract

The invention relates to the technical field of infrared detectors, in particular to a method for analyzing a thin film defect source, which comprises the following steps of: corroding a cadmium zinc telluride substrate to obtain a corroded substrate; testing and analyzing the surface defects of the corroded substrate; epitaxially growing a tellurium-cadmium-mercury thin film on the corroded substrate; testing and analyzing the defects of the tellurium-cadmium-mercury thin film; and comparing the defect of the tellurium-cadmium-mercury film with the surface defect, and analyzing the source of the defect of the tellurium-cadmium-mercury film. Various defects, including partial defects which cannot be detected in the prior art, on the surface of the tellurium-zinc-cadmium substrate before growth can be detected by utilizing the corroded surface, and the defects can be compared and analyzed more accurately with the defects of the grown tellurium-cadmium-mercury film.

Description

Technical Field

[0001] The invention relates to the technical field of infrared detectors, and in particular to a method for analyzing sources of film defects. Background Art

[0002] Based on the mercury cadmium telluride material system, modern infrared detector technology has entered the fast lane of systematic development. Various defects will inevitably occur during the growth process of mercury cadmium telluride thin films used to prepare infrared detectors, and these defects will affect the performance of the detector. In order to optimize the growth process and improve the quality of mercury cadmium telluride thin films, it is necessary to analyze the source of defects. The existing technology detects substrate defects through metallographic microscopes, X-ray diffraction and X-ray topography tests before growth, and compares and analyzes the defects of mercury cadmium telluride thin films after growth; after growth, the substrate or film is thinned / polished / etched, and the sources of some defects are analyzed through the characteristics of the film defect interface. However, the existing technology has the following problems: when the processed and cleaned substrate is inspected with a metallographic microscope before growth, some contamination cannot be detected; when the damage introduced by substrate processing is small, X-ray topography and X-ray double crystal diffraction half-peak width cannot reflect all damage due to insufficient test accuracy; the thinning / polishing / etching process cannot analyze the source of all film defects. Summary of the invention

[0003] In view of the above problems, an object of the present invention is to provide a method for analyzing the sources of defects in mercury cadmium telluride films.

[0004] A method for analyzing the sources of defects in mercury cadmium telluride thin films comprises the following steps:

[0005] Step S1, corroding the cadmium zinc telluride substrate to obtain a corroded substrate;

[0006] Step S2, testing and analyzing the surface defects of the corroded substrate;

[0007] Step S3, epitaxially growing a mercury cadmium telluride thin film on the corroded substrate;

[0008] Step S4, testing and analyzing the defects of the mercury cadmium telluride film;

[0009] Step S5, comparing the defects of the HgCdTe film with the surface defects, and analyzing sources of the defects of the HgCdTe film.

[0010] In the method for analyzing the sources of defects in a mercury cadmium telluride film of the present invention, the cadmium zinc telluride substrate in step S1 is a cadmium zinc telluride substrate that has been processed and cleaned.

[0011] In the method for analyzing the sources of defects in a mercury cadmium telluride film of the present invention, a metallographic microscope is used to perform testing and analysis in step S2.

[0012] In the method for analyzing the sources of defects in a mercury cadmium telluride film of the present invention, the analysis is performed using a metallographic microscope and a scanning electron microscope in step S4.

[0013] In the method for analyzing the sources of defects in a mercury cadmium telluride film described in the present invention, the surface defects in step S2 include defects of the substrate itself, contamination, and processing damage.

[0014] In the method for analyzing the sources of defects in a mercury cadmium telluride film of the present invention, the corrosion in step S1 is mercury corrosion or cadmium corrosion.

[0015] In the method for analyzing the defect sources of a mercury cadmium telluride film of the present invention, when the corrosion is mercury corrosion, the mercury source atmosphere provided by the mercury cadmium telluride mother liquor during epitaxial growth is utilized.

[0016] The method for analyzing the defect sources of a mercury cadmium telluride film of the present invention comprises step S1, corroding the cadmium zinc telluride substrate during epitaxial growth.

[0017] Beneficial effects: The present invention etches a CdZnTe substrate, takes out the etches to test and analyze the surface defects, and then epitaxially grows a HgCdTe film on the etches; tests and analyzes the defects of the HgCdTe film; compares the defects of the HgCdTe film with the surface defects, and analyzes the sources of the defects of the HgCdTe film. Various defects on the surface of the CdZnTe substrate before growth can be detected by using the etches, including some defects that cannot be detected by the prior art, and can be more accurately compared and analyzed with the defects of the HgCdTe film after growth. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 The present invention is a flow chart of a method for analyzing sources of defects in a mercury cadmium telluride film.

[0019] Figure 2a This is an X-ray diffraction phase diagram of the substrate before growth according to an embodiment of the present invention.

[0020] Figure 2b This is a microscope image of a substrate after mercury corrosion according to an embodiment of the present invention.

[0021] Figure 2c This is a microscope image after epitaxial growth of an embodiment of the present invention.

[0022] Figure 3 For the present invention Figure 2a to Figure 2c A partial enlarged view of . DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0025] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments, but they are not intended to limit the present invention.

[0026] Reference Figure 1 , a method for analyzing the sources of defects in mercury cadmium telluride thin films, comprising the following steps:

[0027] Step S1, corroding the cadmium zinc telluride substrate to obtain a corroded substrate;

[0028] Step S2, testing and analyzing the surface defects of the corroded substrate;

[0029] Step S3, epitaxially growing a mercury cadmium telluride thin film on the corroded substrate;

[0030] Step S4, testing and analyzing the defects of the mercury cadmium telluride film;

[0031] Step S5, comparing the defects of the HgCdTe film with the surface defects, and analyzing sources of the defects of the HgCdTe film.

[0032] The present invention etches a CdZnTe substrate, takes out the etches to test and analyze the surface defects of the substrate, epitaxially grows a HgCdTe film on the etches; tests and analyzes the defects of the HgCdTe film; compares the defects of the HgCdTe film with the surface defects, and analyzes the sources of the defects of the HgCdTe film. Various defects on the surface of the CdZnTe substrate before growth can be detected by using the etches, including some defects that cannot be detected by the prior art, and can be more accurately compared and analyzed with the defects of the HgCdTe film after growth, for example, to determine the defects of the HgCdTe film caused by contamination or slight scratches before growth.

[0033] In a preferred embodiment of the present invention, a metallographic microscope is used for testing and analysis in step S2.

[0034] In a preferred embodiment of the present invention, a metallographic microscope and a scanning electron microscope are used for analysis in step S4.

[0035] In a preferred embodiment of the present invention, the corrosion in step S1 is mercury corrosion or cadmium corrosion.

[0036] In a preferred embodiment of the present invention, when the etching in step S1 is mercury etching, the mercury source atmosphere provided by the mercury cadmium telluride mother solution during epitaxial growth is utilized.

[0037] Mercury has different corrosion degrees for different defects on the substrate, such as defects in the substrate itself, contamination, processing damage, etc. This method can detect various defects on the surface of the cadmium zinc telluride substrate before growth, including some defects that cannot be detected by existing technologies, and can perform a more accurate comparative analysis with the defects of the mercury cadmium telluride film after growth.

[0038] In a preferred embodiment of the present invention, the CdZnTe substrate in step S1 is a CdZnTe substrate that has been processed and cleaned.

[0039] In a preferred embodiment of the present invention, in step S1, the CdZnTe substrate is corroded during epitaxial growth. The mercury etching process in step S1 is only to prevent the growth of a HgCdTe film, and the rest is consistent with a normal epitaxial growth process.

[0040] The present invention performs mercury etching on the cleaned substrate, and utilizes the different corrosion degrees of mercury on different defects on the substrate, such as substrate defects, contamination, processing damage, etc., to detect various defects, thereby avoiding the influence of substrate dislocation etching on surface flatness and roughness. Since mercury etching is achieved by the mercury source atmosphere provided by the mercury cadmium telluride mother liquid at high temperature during epitaxial growth, it is an inevitable step in vertical liquid phase epitaxial growth, so the substrate after mercury etching can continue to be used for epitaxial growth of mercury cadmium telluride thin film after testing and analysis.

[0041] Figure 2a-2c The X-ray diffraction morphology of the substrate before growth, the microscope image of the substrate after mercury corrosion and the microscope image after epitaxial growth respectively show the defective mercury corrosion and epitaxial growth results that cannot be detected before growth, as shown in the red frame in the attached figure. Figure 3 for Figure 2a to Figure 2c The red frame in the figure corresponds to the local enlarged image, where: Figure 3 The first column is Figure 2a A partial enlarged view of the contamination 11a, damage (scratch) 12a, and substrate twin line 13a. Figure 3 The second column is Figure 2b Partially enlarged images of 11b, 12b, and 13b. Figure 3 The third column is Figure 2c The present invention compares the surface defects of the etched substrate with the defects of the subsequent epitaxially grown HgCdTe film, and accurately analyzes the defects of the HgCdTe film caused by contamination and micro-damage on the substrate without introducing additional defects.

[0042] Through the description and drawings, typical embodiments of the specific structures of the specific implementation methods are given, and other transformations can be made based on the spirit of the present invention. Although the above invention proposes the existing preferred embodiments, these contents are not intended to be limiting.

[0043] For those skilled in the art, various changes and modifications will undoubtedly be obvious after reading the above description. Therefore, the attached claims should be regarded as covering all changes and modifications of the true intent and scope of the present invention. Any and all equivalent ranges and contents within the scope of the claims should be considered to still be within the intent and scope of the present invention.

Claims

1. A method for analyzing the sources of defects in mercury cadmium telluride thin films, characterized in that: The following steps are involved: Step S1, corroding the cadmium zinc telluride substrate to obtain a corroded substrate; Step S2, testing and analyzing the surface defects of the corroded substrate; Step S3, epitaxially growing a mercury cadmium telluride thin film on the corroded substrate; Step S4, testing and analyzing the defects of the mercury cadmium telluride film; Step S5, comparing the defects of the mercury cadmium telluride film with the surface defects, and analyzing sources of the defects of the mercury cadmium telluride film.

2. The method for analyzing the defect sources of mercury cadmium telluride thin films according to claim 1, characterized in that: The CdZnTe substrate in step S1 is a CdZnTe substrate that has been processed and cleaned.

3. The method for analyzing the defect sources of mercury cadmium telluride thin films according to claim 1, characterized in that: In step S2, a metallographic microscope is used to perform testing and analysis.

4. The method for analyzing the defect sources of mercury cadmium telluride thin films according to claim 1, characterized in that: In step S4, analysis is performed using a metallographic microscope and a scanning electron microscope.

5. The method for analyzing defect sources of mercury cadmium telluride thin films according to claim 1, characterized in that: The surface defects in step S2 include defects of the substrate itself, contamination, and processing damage.

6. The method for analyzing defect sources of mercury cadmium telluride thin films according to claim 1, characterized in that: The corrosion in step S1 is mercury corrosion or cadmium corrosion.

7. The method for analyzing defect sources of mercury cadmium telluride thin films according to claim 1, characterized in that: When the etching in step S1 is mercury etching, the mercury source atmosphere provided by the mercury cadmium telluride mother solution during epitaxial growth is utilized.

8. The method for analyzing defect sources of mercury cadmium telluride thin films according to claim 1, characterized in that: Step S1, corroding the CdZnTe substrate during epitaxial growth.

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