CN112458543B - A kind of surface treatment method of CZT radiation detection film material - Google Patents

Abstract

The invention relates to a method for surface treatment of a CZT radiation detection film material, which comprises a special rough polishing liquid and a fine polishing liquid, adopts an external 8-shaped grinding and polishing method for the film material to grind the rough polishing and fine polishing film surfaces, and configures a special corrosive liquid , take it out after 30s of corrosion, then ultrasonically clean with methanol for 30s, then ultrasonically clean with acetone, alcohol and distilled water for 20min, and finally blow dry with nitrogen to complete the corrosion; then perform oxygen ion and argon etching to complete the surface of the film material . The method improves the surface degree of the CZT polycrystalline film by polishing, corroding and etching the surface of the CZT polycrystalline thick film, and greatly improves the photoelectric performance of the thick film detector.

Description

A kind of surface treatment method of CZT radiation detection film material

technical field

The invention belongs to the surface treatment method of film materials, in particular to the surface treatment method of cadmium zinc telluride semiconductor polycrystalline film materials.

Background technique

Cd _1-x Zn _x Te is a new type of room temperature semiconductor nuclear radiation detector material with excellent performance. This material has the following advantages: (1) Large atomic number, relatively large resistance to x-rays, 1mm thick CZT wafer It can completely absorb hard X-rays with energy lower than 60keV. For γ-rays of 122keV, a 2mm thick CZT wafer can absorb 70%; (2) Excellent carrier transport characteristics, carrier mobility and lifetime product (μτ value ) higher than 2×10 ^-3 cm ² /V; (3) relatively wide band gap energy, and its room temperature band gap is continuously adjustable between 1.49eV and 2.26eV. Compared with CZT wafers, the preparation of CZT polycrystalline film can greatly reduce the cost of preparing radiation detection devices, and can prepare flat panel detectors with uniformity, density, low leakage current, large switching ratio, and large area. The roughness of the film surface will affect the performance of the device. Generally, the methods to reduce the film roughness include: (1) Optimizing the growth process parameters in the early stage to make the surface of the grown film as flat as possible with low roughness; (2) Generally, the growth of polycrystalline films The surface is relatively rough or there are some stains, and some surface treatment methods are required to reduce the surface roughness in the later stage, reduce the surface leakage current and improve the signal-to-noise ratio of the device. The surface treatment of the grown CZT film can greatly optimize the photoelectric performance of the device.

Although the use of CZT polycrystalline film can greatly reduce the cost of manufacturing radiation detection devices, and can prepare flat panel detectors that are uniform, dense, low leakage current, large switch ratio, and large area. However, the surface roughness of the film will seriously affect the performance of the device, and the surface of the CZT thick film prepared by the short-distance sublimation method is uneven and rough, and the photoelectric performance of the detector prepared without surface treatment is relatively poor.

Contents of the invention

technical problem to be solved

In order to avoid the deficiencies of the prior art, the present invention proposes a surface treatment method for CZT radiation detection thin film materials. By polishing, corroding and etching the surface of the CZT polycrystalline thick film, the thick film detection is greatly improved. The photoelectric performance of the device.

Technical solutions

A surface treatment method for a CZT radiation detection film material, characterized in that the steps are as follows:

Step 1. Grinding: Grinding and polishing the surface of the film, then ultrasonic cleaning with acetone, alcohol and distilled water, and finally drying with nitrogen;

Step 2, rough throwing: use the rough throwing liquid, adopt the external 8-shaped grinding and polishing method to carry out rough throwing on the surface of the film, and use distilled water to repeatedly ultrasonically clean until there is no residual white MgO on the surface; the rough throwing liquid: according to the mass percentage of MgO: Deionization = 20:: 100 to configure coarse throwing liquid;

Step 3, fine polishing: use fine polishing liquid, adopt external 8-shaped grinding and polishing method to carry out fine polishing on the surface of the film, and use distilled water to ultrasonically clean for 5 minutes every polishing 20s to prevent the surface of the film from being corroded; repeat the above operation several times; Throwing liquid: Hydrogen peroxide according to volume percentage: coarse liquid = 1: 1 to configure fine liquid

Step 4, Corrosion: After immersing the film in the corrosion solution for 30 seconds, take it out, then ultrasonically clean it with methanol for 30 seconds, then use acetone, alcohol and distilled water to clean it ultrasonically for 20 minutes, and finally dry it with nitrogen; the corrosion solution: Methanol according to the volume percentage: Bromine = 50: 1.5 configure bromine methanol corrosion solution;

Step 5. Oxygen ion etching: use a plasma etching machine to etch the surface of the film, the gas is oxygen, the etching power is 10W, the gas flow rate is 80sccm, the working pressure is 5Pa, and the etching time is 2min;

Step 6, argon etching: use a plasma etching machine to etch the surface of the film, the gas is argon, the etching power is 5W, the oxygen flow rate is 90sccm, the working pressure is 5Pa, and the etching time is 5min.

The grinding and polishing of the surface of the film in the step 1 is: using sandpaper and adopting an external figure-of-eight grinding and polishing method.

The sandpaper used is 2000 and 5000 mesh sandpaper.

Said ultrasonic cleaning with acetone, alcohol and distilled water for 20min.

The MgO powder is MgO powder of analytical purity or above.

Beneficial effect

The surface treatment method of a CZT radiation detection film material proposed by the present invention is equipped with special rough polishing liquid and fine polishing liquid, and adopts the external 8-shaped grinding and polishing method for the film material to grind the surface of the rough polishing and fine polishing film, and configures a special corrosion After 30s of corrosion, take it out, then ultrasonically clean it with methanol for 30s, then ultrasonically clean it with acetone, alcohol and distilled water for 20min, and finally dry it with nitrogen to complete the corrosion; then perform oxygen ion and argon etching to complete the thin film material surface. The method improves the surface degree of the CZT polycrystalline film by polishing, corroding and etching the surface of the CZT polycrystalline thick film, and greatly improves the photoelectric performance of the thick film detector.

Description of drawings

Fig. 1: Schematic flow diagram of the present invention

Detailed ways

Now in conjunction with embodiment, accompanying drawing, the present invention will be further described:

Example 1

S1. Grinding: Use 2000 and 5000 mesh sandpaper successively, and use the external 8-shaped grinding and polishing method to polish the surface of the film until the surface of the film is flat and no obvious grains can be seen with the naked eye, and then ultrasonically clean with acetone, alcohol and distilled water for 20 minutes , and finally blow dry with nitrogen;

S2. Configure the coarse throwing liquid: use MgO powder of analytical purity and above purity, and configure the rough throwing liquid according to the ratio of mass percentage MgO: deionization = 20:100;

S3. Coarse polishing: use the rough polishing liquid configured in S2, and use the external 8-shaped grinding and polishing method to roughly polish the surface of the film until no scratches can be seen on the surface of the film, and finally use distilled water to repeatedly ultrasonically clean it until there is no residue on the surface. White MgO;

S4, configuration fine throwing liquid: according to volume percentage hydrogen peroxide: the polishing liquid of S2 configuration=1:1 ratio configures fine throwing liquid;

S5. Fine polishing: Use the coarse polishing solution configured in S4 to finely polish the surface of the film by means of an external 8-shaped grinding and polishing method. Use distilled water to ultrasonically clean for 5 minutes every 20 seconds of polishing to prevent the surface of the film from being corroded. Repeat the above operation several times until the surface is as smooth as a mirror under naked eye observation;

S6, configure the corrosion solution: configure the bromine methanol corrosion solution according to the ratio of volume percentage methanol:bromine=50:1.5;

S7. Corrosion: immerse the film in the corrosive solution configured in S6 for 30 seconds and then take it out, then ultrasonically clean it with methanol for 30 seconds, then ultrasonically clean it with acetone, alcohol and distilled water for 20 minutes, and finally dry it with nitrogen;

S8. Oxygen ion etching: use a plasma etching machine to etch the surface of the film, the gas is oxygen, the etching power is 10W, the gas flow rate is 80sccm, the working pressure is 5Pa, and the etching time is 2min;

S9. Argon etching: use a plasma etching machine to etch the surface of the film, the gas is argon, the etching power is 5W, the oxygen flow rate is 90sccm, the working pressure is 5Pa, and the etching time is 5min.

Example 2

S1. Grinding: Use 2000 and 5000 mesh sandpaper successively, and use the external 8-shaped grinding and polishing method to polish the surface of the film until the surface of the film is flat and no obvious grains can be seen with the naked eye, and then ultrasonically clean with acetone, alcohol and distilled water for 20 minutes , and finally blow dry with nitrogen;

S2. Configure the coarse throwing liquid: use MgO powder of analytical purity and above purity, and configure the rough throwing liquid according to the ratio of mass percentage MgO: deionization = 20:100;

S3. Coarse polishing: use the rough polishing liquid configured in S2, and use the external 8-shaped grinding and polishing method to roughly polish the surface of the film until no scratches can be seen on the surface of the film, and finally use distilled water to repeatedly ultrasonically clean it until there is no residue on the surface. White MgO;

S4, configuration fine throwing liquid: according to volume percentage hydrogen peroxide: the polishing liquid of S2 configuration=1:1 ratio configures fine throwing liquid;

S5. Fine polishing: Use the coarse polishing solution configured in S4 to finely polish the surface of the film by means of an external 8-shaped grinding and polishing method. Use distilled water to ultrasonically clean for 5 minutes every 20 seconds of polishing to prevent the surface of the film from being corroded. Repeat the above operation several times until the surface is as smooth as a mirror under naked eye observation;

S6, configure corrosion solution: configure bromine methanol corrosion solution according to the ratio of volume percentage methanol:bromine=50:2;

S7. Corrosion: immerse the film in the corrosive solution configured in S6 for 30 seconds and then take it out, then ultrasonically clean it with methanol for 30 seconds, then ultrasonically clean it with acetone, alcohol and distilled water for 20 minutes, and finally dry it with nitrogen;

S8. Oxygen ion etching: use a plasma etching machine to etch the surface of the film, the gas is oxygen, the etching power is 10W, the gas flow rate is 80sccm, the working pressure is 5Pa, and the etching time is 2min;

S9. Argon etching: use a plasma etching machine to etch the surface of the film, the gas is argon, the etching power is 5W, the oxygen flow rate is 90sccm, the working pressure is 5Pa, and the etching time is 5min.

Example 3

S1. Grinding: Use 2000 and 5000 mesh sandpaper successively, and use the external 8-shaped grinding and polishing method to polish the surface of the film until the surface of the film is flat and no obvious grains can be seen with the naked eye, and then ultrasonically clean with acetone, alcohol and distilled water for 20 minutes , and finally blow dry with nitrogen;

S2. Configure the coarse throwing liquid: use MgO powder of analytical purity and above purity, and configure the rough throwing liquid according to the ratio of mass percentage MgO: deionization = 20:100;

S3. Coarse polishing: use the rough polishing liquid configured in S2, and use the external 8-shaped grinding and polishing method to roughly polish the surface of the film until no scratches can be seen on the surface of the film, and finally use distilled water to repeatedly ultrasonically clean it until there is no residue on the surface. White MgO;

S4, configuration fine throwing liquid: according to volume percentage hydrogen peroxide: the polishing liquid of S2 configuration=1:1 ratio configures fine throwing liquid;

S5. Fine polishing: Use the coarse polishing solution configured in S4 to finely polish the surface of the film by means of an external 8-shaped grinding and polishing method. Use distilled water to ultrasonically clean for 5 minutes every 20 seconds of polishing to prevent the surface of the film from being corroded. Repeat the above operation several times until the surface is as smooth as a mirror under naked eye observation;

S6, configure the corrosion solution: configure the bromine methanol corrosion solution according to the ratio of volume percentage methanol:bromine=50:1.5;

S7. Corrosion: immerse the film in the corrosive solution configured in S6 for 30 seconds and then take it out, then ultrasonically clean it with methanol for 30 seconds, then ultrasonically clean it with acetone, alcohol and distilled water for 20 minutes, and finally dry it with nitrogen;

S8. Oxygen ion etching: use a plasma etching machine to etch the surface of the film, the gas is oxygen, the etching power is 15W, the gas flow rate is 80sccm, the working pressure is 5Pa, and the etching time is 10min;

S9. Argon gas etching: use a plasma etching machine to etch the surface of the film, the gas is argon, the etching power is 10W, the oxygen flow rate is 90sccm, the working pressure is 5Pa, and the etching time is 10min.

Claims (5)

1. a surface treatment method of CZT radiation detection thin film material is characterized in that the steps are as follows: Step 1. Grinding: Grinding and polishing the surface of the film, then ultrasonic cleaning with acetone, alcohol and distilled water, and finally drying with nitrogen; Step 2, rough throwing: use the rough throwing liquid, adopt the external 8-shaped grinding and polishing method to carry out rough throwing on the surface of the film, and use distilled water to repeatedly ultrasonically clean until there is no residual white MgO on the surface; the rough throwing liquid: according to the mass percentage of MgO: Deionized water = 20: 100 to configure coarse throwing liquid; Step 3, fine polishing: use fine polishing liquid, adopt external 8-shaped grinding and polishing method to carry out fine polishing on the surface of the film, and use distilled water to ultrasonically clean for 5 minutes every polishing 20s to prevent the surface of the film from being corroded; repeat the above operation several times; Throwing liquid: according to the volume percentage of hydrogen peroxide: coarse liquid = 1: 1 to configure fine liquid; Step 4, Corrosion: After immersing the film in the corrosion solution for 30 seconds, take it out, then ultrasonically clean it with methanol for 30 seconds, then use acetone, alcohol and distilled water to clean it ultrasonically for 20 minutes, and finally dry it with nitrogen; the corrosion solution: Methanol according to the volume percentage: Bromine = 50: 1.5 configure bromine methanol corrosion solution; Step 5. Oxygen ion etching: use a plasma etching machine to etch the surface of the film, the gas is oxygen, the etching power is 10W, the gas flow rate is 80sccm, the working pressure is 5Pa, and the etching time is 2min; Step 6, argon etching: use a plasma etching machine to etch the surface of the film, the gas is argon, the etching power is 5W, the oxygen flow rate is 90sccm, the working pressure is 5Pa, and the etching time is 5min. 2. The surface treatment method of the CZT radiation detection thin film material according to claim 1, characterized in that: the grinding and polishing of the thin film surface in the step 1 is carried out by sandpaper using an external 8-shaped grinding and polishing method. 3. The surface treatment method of the CZT radiation detection film material according to claim 2, characterized in that: the sandpaper adopts 2000 and 5000 mesh sandpaper. 4. The surface treatment method of the CZT radiation detection film material according to claim 1, characterized in that: in step 1, use acetone, alcohol and distilled water to ultrasonically clean for 20 minutes. 5. The method for surface treatment of the CZT radiation detection thin film material according to claim 1, characterized in that: the MgO powder is analytically pure or above pure MgO powder.

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