Device and method for automatically testing thickness of large-size silicon-based cadmium mercury telluride film

Abstract

The application discloses a device and a method for automatically testing the thickness of large-size silicon-based tellurium-cadmium-mercury film, and the device is characterized in that a rotating table for automatically rotating a sample is designed, so that a small-stroke sample table can test the function of the large-size silicon-based tellurium-cadmium-mercury film material, and the test results of four quadrants can be spliced by combining with data splicing software, so that the Mapping thickness of the 6-inch silicon-based tellurium-cadmium-mercury film material can be accurately measured, and the problem that the existing thickness testing device cannot test the thickness of the large-size silicon-based tellurium-cadmium-mercury film material is effectively solved.

Description

Technical Field

[0001] This invention relates to the field of infrared semiconductor materials technology, and in particular to an apparatus and method for automatically testing the thickness of large-size silicon-based mercury cadmium telluride thin films. Background Technology

[0002] In the field of infrared semiconductor materials, HgCdTe, being a direct bandgap semiconductor with an adjustable bandgap that covers the entire infrared band, is an ideal material for infrared detectors. It has been widely used in the fabrication of various types of infrared detectors since the 1970s and is currently the most widely used detector material in the infrared detection field. After nearly thirty years of continuous development, it is now possible to fabricate many high-quality Hg1-xCdxTe epitaxial films and high-performance infrared detector devices using various methods such as LPE, MOVPE, and MBE. Large-area, low-cost HgCdTe films require molecular beam epitaxy (MBE) technology for fabrication.

[0003] For mercury cadmium telluride (HCdM) thin film materials, after epitaxy, Fourier transform infrared (FTIR) spectroscopy is needed to perform composition, thickness, and cutoff wavelength mapping tests to obtain information on the composition, thickness, and cutoff wavelength at various locations throughout the material. This information is then fed back into the design of the growth process to adjust the material composition ratio and growth thickness. However, the sample stage travel of FTIR spectrometers is relatively small, making it impossible to perform characterization tests on materials of large sizes, such as 6 inches. Summary of the Invention

[0004] This invention provides an apparatus and method for automatically testing the thickness of large-size silicon-based mercury cadmium telluride thin films, thereby solving the problem that existing technologies cannot perform thickness testing on large-size mercury cadmium telluride thin film materials.

[0005] In a first aspect, the present invention provides an apparatus for automatically testing the thickness of large-size silicon-based mercury cadmium telluride thin films. The apparatus includes: a rotating stage, and a sample cell for the silicon-based mercury cadmium telluride thin film to be tested and a background sheet disposed on the rotating stage. The rotating stage is also connected to a power unit.

[0006] The power device controls the rotating stage to rotate around its center point, thereby rotating the silicon-based mercury cadmium telluride (HCdT) film sample in the test sample slot. The rotation angle of the rotating stage is controlled so that the HCdT film sample can be rotated to any test position. The thickness of the HCdT film sample is then measured using a testing device.

[0007] Optionally, a reset sensor is also provided on the rotating platform;

[0008] The reset sensor is used to record the initial test position of the rotary table, and the rotary table is returned to the initial test position by controlling the reset sensor.

[0009] Optionally, the outer diameter of the rotating stage is larger than the outer diameter of the silicon-based mercury cadmium telluride thin film sample to be tested.

[0010] Optionally, the rotating platform is provided with a cross-shaped dividing area, the center of which coincides with the center of the rotating platform, and the rotating platform is divided into four quadrants by the cross-shaped dividing area.

[0011] Optionally, the power unit is a motor.

[0012] Secondly, the present invention provides a method for automatically testing the thickness of large-size silicon-based mercury cadmium telluride thin films using any of the above-described devices. The method includes: mounting a rotary table containing a sample of the silicon-based mercury cadmium telluride thin film to be tested on the sample stage of the testing device; setting a background film for testing on the upper right side of the rotary table; setting the test size and test step; after the testing device acquires the spectrum of the background film, testing the sample of the silicon-based mercury cadmium telluride thin film to be tested, obtaining and storing test results in different quadrants in sequence, and splicing the test results of each quadrant to obtain the overall test result of the sample of the silicon-based mercury cadmium telluride thin film to be tested.

[0013] Optionally, the reset sensor can be reset to zero before testing.

[0014] Optionally, the silicon-based mercury cadmium telluride thin film sample to be tested is tested, and test results in different quadrants are obtained and stored sequentially. This includes: testing the silicon-based mercury cadmium telluride thin film sample to be tested in the first quadrant to obtain a first test result; controlling the rotary table to rotate 90° clockwise to test the silicon-based mercury cadmium telluride thin film sample to be tested in the second quadrant to obtain a second test result; controlling the rotary table to select and sequentially test to obtain a third test result and a fourth test result in the third and fourth quadrants, and saving the first test result, the second test result, the third test result, and the fourth test result.

[0015] Optionally, the diameter of the silicon-based mercury cadmium telluride film to be tested is greater than 6 inches.

[0016] Thirdly, the present invention provides a computer-readable storage medium storing a computer program of signal mapping, which, when executed by at least one processor, implements the method for automatically testing the thickness of large-size silicon-based mercury cadmium telluride thin films as described above.

[0017] The beneficial effects of this invention are as follows:

[0018] This invention achieves the capability to test silicon-based mercury cadmium telluride (HCdT) thin film materials of up to 6 inches in size by designing an automatic rotating sample stage. Combined with data stitching software, the test results from the four quadrants can be stitched together, thereby enabling accurate determination of the mapping thickness of 6-inch silicon-based HCdT thin film materials. This effectively solves the problem that existing methods cannot test the thickness of large-sized silicon-based HCdT thin film materials.

[0019] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and in order to make the above and other objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described below. Attached Figure Description

[0020] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0021] Figure 1 This is a schematic diagram of the structure of an automatic device for testing the thickness of large-size silicon-based mercury cadmium telluride thin films provided in the first embodiment of the present invention;

[0022] Figure 2 This is a flowchart illustrating a method for automatically testing the thickness of large-size silicon-based mercury cadmium telluride thin films according to the first embodiment of the present invention.

[0023] Figure description: 1 Rotary stage, 2 Sample tank, 3 Background film, 4 Power unit, 5 Reset sensor. Detailed Implementation

[0024] This invention addresses the problem of existing methods being unable to test the thickness of large-sized silicon-based mercury cadmium telluride (HCdT) thin films. It achieves this by designing an automatically rotating sample stage, enabling the testing of larger HCdT thin films, such as 6 inches, with a short sample travel. Combined with data stitching software, test results from the four quadrants can be stitched together, thereby achieving accurate measurement of the mapping thickness of a 6-inch HCdT thin film. The invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and do not limit the scope of the invention.

[0025] The first embodiment of the present invention provides an apparatus for automatically testing the thickness of large-size silicon-based mercury cadmium telluride thin films, see [link to relevant documentation]. Figure 1The device includes: a rotating stage 1, a sample cell 2 for a silicon-based mercury cadmium telluride thin film to be tested and a background sheet 3 disposed on the rotating stage 1, and the rotating stage 1 is also connected to a power unit 4.

[0026] The power device 4 controls the rotating stage 1 to rotate around its center point, thereby rotating the silicon-based mercury cadmium telluride thin film sample to be tested on the sample tank 2. The rotation angle of the rotating stage 1 is controlled so that the sample to be tested can be rotated to any test position, and the thickness of the sample to be tested can be measured by the testing device.

[0027] In practice, the rotary table 1 is mounted on the sample stage of the existing testing device, and the existing testing device is used to test the sample to be tested in the sample tank 2.

[0028] Furthermore, the device described in this embodiment of the invention may also be provided with a reset sensor 5, which is disposed on the rotary table 1. The reset sensor 5 is used to record the initial test position of the rotary table 1, and the rotary table 1 is returned to the initial test position by controlling the reset sensor 5.

[0029] It should be noted that the outer diameter of the rotating stage 1 in this embodiment of the invention is larger than the outer diameter of the silicon-based mercury cadmium telluride thin film sample to be tested. The dimensions of the rotating stage 1 and the sample groove 2 thereon can be arbitrarily set according to actual needs. This invention will not describe this in detail, but generally aims to meet the testing requirements of the sample to be tested.

[0030] In specific implementation, for ease of testing, the rotary table 1 in this embodiment of the invention is provided with a cross-shaped dividing area, the center of which coincides with the center of the rotary table 1, and the rotary table 1 is divided into four quadrants by the cross-shaped dividing area.

[0031] In other words, the present invention uses a reset sensor 5 to record the initial position of the sample to be tested, and tests the sample to be tested separately according to different quadrants. Then, the test results of the four quadrants are combined to obtain the final test result.

[0032] The second embodiment of the present invention provides a method for automatically testing the thickness of large-size silicon-based mercury cadmium telluride thin films using any of the devices described in the first embodiment of the present invention. See [link to documentation]. Figure 2 The method includes:

[0033] S201. A rotating stage containing the silicon-based mercury cadmium telluride thin film sample to be tested is installed on the sample stage of the testing device, and a background sheet for testing is set on the rotating stage.

[0034] S202. Set the test size and test step distance. After the test device collects the background spectrum, it tests the silicon-based mercury cadmium telluride thin film sample to be tested, obtains the test results of different quadrants in sequence and stores them, and splices the test results of each quadrant to obtain the overall test result of the silicon-based mercury cadmium telluride thin film sample to be tested.

[0035] In practice, before testing, the reset sensor is controlled to reset to zero.

[0036] Furthermore, in this embodiment of the invention, the silicon-based mercury cadmium telluride thin film sample to be tested is tested, and test results in different quadrants are obtained and stored sequentially. This includes: testing the silicon-based mercury cadmium telluride thin film sample to be tested in the first quadrant to obtain a first test result; controlling the rotary table to rotate 90° clockwise to test the silicon-based mercury cadmium telluride thin film sample to be tested in the second quadrant to obtain a second test result; controlling the rotary table to select and sequentially test to obtain a third test result and a fourth test result in the third and fourth quadrants, and saving the first test result, the second test result, the third test result, and the fourth test result.

[0037] The following will provide a detailed explanation and illustration of the method described in this invention through a specific test example:

[0038] For mercury cadmium telluride (HCdT) thin film materials, after epitaxy, Fourier transform infrared (FTIR) spectroscopy is required to perform mapping tests on its composition, thickness, and cutoff wavelength. This information is used to obtain data on the composition, thickness, and cutoff wavelength at various locations throughout the material, which is then fed back into the growth process design to adjust the material composition ratio and growth thickness. However, the Fourier transform infrared spectroscopy sample stage has a small travel distance, making it impossible to perform characterization tests on 6-inch materials. Therefore, we developed a rotating stage capable of automatically rotating and holding 6-inch materials. Precise control of the rotating stage is achieved through a servo motor driven by software, and data stitching software written in Python is used to realize mapping tests on 6-inch silicon-based HCdT materials.

[0039] Existing platforms can only move in three dimensions (X, Y, Z), and can only move in the XY plane during testing. The test sample size is relatively small, and the entire sample is characterized by splicing the test results from multiple regions.

[0040] The present invention is based on the XYZ three-dimensional moving platform of the device, with the addition of a rotary table with a self-rotation function. The servo motor drives the sample in the sample cell to rotate through gear transmission. Sensor points are designed on the sample cell to realize the control of the sample in the sample cell to automatically restore the initial position.

[0041] From a software design perspective: (a) Rotary stage control software, controlling rotation, rotation direction, rotation angle, and reset functions; (b) Test result rotation and stitching software, which divides the sample evenly into four quadrants for testing, and the test results for the four regions are in EXCEL table format. Software written in Python processes the test results of the four regions according to the test order: the first quadrant is used as the baseline, and the data is not processed. The sample stage rotates the second quadrant portion of the sample 90° clockwise to the first quadrant for testing. The result needs to be rotated 90° counterclockwise and placed in the second quadrant of the test results, then stitched with the first quadrant data. Similarly, the test results for the third and fourth quadrant portions of the sample need to be rotated 180° and 270° counterclockwise respectively and placed in the third and fourth quadrants of the test results, then stitched with the data from the first and second quadrants, thus obtaining the test results for the entire sample; (c) Adjustable data processing, because the step size set in the test determines the amount of data in each quadrant, the rotation and stitching of the data in the four regions can be achieved by modifying the row and column values ​​of the data in the EXCEL table using the software's row and column values.

[0042] By adding a rotating sample stage, the 6-inch sample is divided into four quadrants. The required travel distance for testing in each quadrant is 76.2mm × 76.2mm (6 × 25.4 ÷ 2 = 76.2), which effectively solves the problem that the original sample stage with a travel distance of 78mm × 128mm could not test 6-inch samples. The data stitching software effectively solves the problem of rotating and stitching the test results for each quadrant.

[0043] The following example illustrates the entire testing process of the 6-inch silicon-based mercury cadmium telluride Fourier transform test with automatic sample rotation according to the present invention:

[0044] Step A: Place the 6-inch silicon-based mercury cadmium telluride material into the fixture of the rotary table;

[0045] Step B: Install the rotating stage containing the sample onto the original sample stage, and place the background film for the test on the upper right side of the rotating stage;

[0046] Step C: Reset the device to zero using the control software;

[0047] Step D: Use the testing software to set the test size and test step size;

[0048] Step E: Perform the test. After the equipment collects the background spectrum, it tests the sample and obtains the test results in the first quadrant, which are stored in Sheet1 of the Excel file.

[0049] Step F: Rotate the sample stage 90° clockwise using the platform control software, repeat step E, and obtain the test results for the second quadrant. Store the results in sheet 2 of the Excel file. Test the results for the third and fourth quadrants in sequence.

[0050] Step G: Using the software written in Python, input the number of rows and columns of the data, open the corresponding Excel file, and immediately generate the entire test result after splicing. Delete the extra data to get the final result.

[0051] As can be seen, the rotary table described in this invention can divide a 6-inch sample into four quadrants. The required travel distance for testing in each quadrant is 76.2mm × 76.2mm (6 × 25.4 ÷ 2 = 76.2), which effectively solves the problem that the original sample stage with a travel distance of 78mm × 128mm cannot test a 6-inch sample. The data stitching software effectively solves the problem of rotating and stitching the test results for each quadrant.

[0052] The above detailed description of the invention is provided to enable those skilled in the art to understand it. However, it is conceivable that, regarding sample size, materials with a diameter or side length greater than 78 mm (4 inches, 5 inches, 6 inches, 70 mm × 70 mm, etc.) can be tested and characterized using this method. Regarding materials, the primary material is mercury cadmium telluride thin film, and the substrate material can be silicon, cadmium zinc telluride, etc. Other changes and modifications can be made without departing from the scope of the claims of this invention, and all such changes and modifications are within the protection scope of this invention.

[0053] The relevant content of the embodiments of the present invention can be understood by referring to the first embodiment of the present invention, and will not be discussed in detail here.

[0054] A third embodiment of the present invention provides a computer-readable storage medium storing a computer program that maps signals. When executed by at least one processor, the computer program implements the method for automatically testing the thickness of large-size silicon-based mercury cadmium telluride thin films as described in any of the first embodiments of the present invention.

[0055] The relevant content of the embodiments of the present invention can be understood by referring to the first embodiment of the present invention, and will not be discussed in detail here.

[0056] Although preferred embodiments of the invention have been disclosed for illustrative purposes, those skilled in the art will recognize that various modifications, additions, and substitutions are possible, and therefore the scope of the invention should not be limited to the embodiments described above.

Claims

1. A device for automatically testing the thickness of a large size silicon based cadmium mercury telluride thin film, characterized in that, The device comprises a rotating table, a sample groove of a silicon-based tellurium cadmium mercury film to be measured and a background sheet arranged on the rotating table, and the rotating table is further connected with a power device; The rotating table is controlled to rotate around the center point of the rotating table by the power device, so as to drive the sample of the silicon-based tellurium cadmium mercury film to be measured on the sample groove to rotate, and the rotating angle of the rotating table is controlled, so that the sample of the silicon-based tellurium cadmium mercury film to be measured is rotated to any to-be-measured position, and the thickness of the sample of the silicon-based tellurium cadmium mercury film to be measured is measured by a testing device. The diameter of the sample of the silicon-based tellurium cadmium mercury film to be measured is greater than 6 inches.

2. The apparatus of claim 1, wherein, The rotating table is further provided with a reset sensor. The reset sensor is used to record the initial testing position of the rotating table, and the rotating table is returned to the initial testing position by controlling the reset sensor.

3. The device according to claim 1, wherein The outer diameter size of the rotating table is greater than the outer diameter size of the sample of the silicon-based tellurium cadmium mercury film to be measured.

4. The device according to any one of claims 1-3, wherein The rotating table is provided with a cross-division area, the center of the cross-division area coincides with the center of the rotating table, and the rotating table is divided into four quadrants by the cross-division area.

5. The device according to any one of claims 1-3, wherein The power device is a motor.

6. A method for automatically testing the thickness of large-size silicon-based mercury cadmium telluride thin films using the apparatus of claim 1, characterized in that, The device comprises: The rotating table provided with the sample of the silicon-based tellurium cadmium mercury film to be measured is installed on the sample table of the testing device, and a background sheet used for testing is arranged on the rotating table; The testing size and the testing step distance are set, the testing device collects the spectrum of the background sheet, then tests the sample of the silicon-based tellurium cadmium mercury film to be measured, sequentially obtains the testing results of different quadrants and stores the testing results, and splices the testing results of the quadrants to obtain the overall testing result of the sample of the silicon-based tellurium cadmium mercury film to be measured.

7. The method according to claim 6, wherein Before testing, the reset sensor is controlled to reset to zero.

8. The method according to claim 6 or 7, characterized in that, The sample of the silicon-based tellurium cadmium mercury film to be measured is tested, and the testing results of different quadrants are sequentially obtained and stored, including: The sample of the silicon-based tellurium cadmium mercury film to be measured in the first quadrant is tested to obtain a first testing result; The rotating table is controlled to rotate clockwise by 90°, the sample of the silicon-based tellurium cadmium mercury film to be measured in the second quadrant is tested to obtain a second testing result, the rotating table is controlled to rotate, the third testing result and the fourth testing result of the third quadrant and the fourth quadrant are sequentially obtained, and the first testing result, the second testing result, the third testing result and the fourth testing result are saved.

9. A computer-readable storage medium, characterized in that, The computer readable storage medium stores a computer program of signal mapping, and the computer program is executed by at least one processor to implement the method for automatically testing the thickness of the large-size silicon-based tellurium cadmium mercury film according to claim 6.

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