CN115161773B - Damage-free defect control technology for large-size CdZnTe single crystal - Google Patents
Damage-free defect control technology for large-size CdZnTe single crystal Download PDFInfo
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- 239000013078 crystal Substances 0.000 title claims abstract description 75
- 229910004611 CdZnTe Inorganic materials 0.000 title claims abstract description 46
- 230000007547 defect Effects 0.000 title claims abstract description 38
- 238000005516 engineering process Methods 0.000 title abstract description 22
- 238000000137 annealing Methods 0.000 claims abstract description 100
- 239000007791 liquid phase Substances 0.000 claims abstract description 49
- 238000000034 method Methods 0.000 claims abstract description 43
- 239000007788 liquid Substances 0.000 claims abstract description 7
- 239000012071 phase Substances 0.000 claims abstract description 6
- 238000001556 precipitation Methods 0.000 claims abstract description 3
- 238000012545 processing Methods 0.000 claims abstract description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 48
- 238000005498 polishing Methods 0.000 claims description 29
- 229910052757 nitrogen Inorganic materials 0.000 claims description 24
- YKYOUMDCQGMQQO-UHFFFAOYSA-L cadmium dichloride Chemical compound Cl[Cd]Cl YKYOUMDCQGMQQO-UHFFFAOYSA-L 0.000 claims description 20
- 238000010438 heat treatment Methods 0.000 claims description 20
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 19
- 238000004140 cleaning Methods 0.000 claims description 19
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 19
- 239000003795 chemical substances by application Substances 0.000 claims description 18
- 239000008367 deionised water Substances 0.000 claims description 17
- 229910021641 deionized water Inorganic materials 0.000 claims description 17
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims description 16
- 238000001816 cooling Methods 0.000 claims description 12
- 238000001035 drying Methods 0.000 claims description 12
- -1 polytetrafluoroethylene Polymers 0.000 claims description 11
- 229920001343 polytetrafluoroethylene Polymers 0.000 claims description 11
- 239000004810 polytetrafluoroethylene Substances 0.000 claims description 11
- 230000003287 optical effect Effects 0.000 claims description 9
- WUPHOULIZUERAE-UHFFFAOYSA-N 3-(oxolan-2-yl)propanoic acid Chemical compound OC(=O)CCC1CCCO1 WUPHOULIZUERAE-UHFFFAOYSA-N 0.000 claims description 6
- LHQLJMJLROMYRN-UHFFFAOYSA-L cadmium acetate Chemical compound [Cd+2].CC([O-])=O.CC([O-])=O LHQLJMJLROMYRN-UHFFFAOYSA-L 0.000 claims description 6
- XIEPJMXMMWZAAV-UHFFFAOYSA-N cadmium nitrate Inorganic materials [Cd+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O XIEPJMXMMWZAAV-UHFFFAOYSA-N 0.000 claims description 6
- QCUOBSQYDGUHHT-UHFFFAOYSA-L cadmium sulfate Chemical compound [Cd+2].[O-]S([O-])(=O)=O QCUOBSQYDGUHHT-UHFFFAOYSA-L 0.000 claims description 6
- 229910000331 cadmium sulfate Inorganic materials 0.000 claims description 6
- 229910052980 cadmium sulfide Inorganic materials 0.000 claims description 6
- NMHMNPHRMNGLLB-UHFFFAOYSA-N phloretic acid Chemical compound OC(=O)CCC1=CC=C(O)C=C1 NMHMNPHRMNGLLB-UHFFFAOYSA-N 0.000 claims description 6
- 230000001681 protective effect Effects 0.000 claims description 5
- 239000012298 atmosphere Substances 0.000 claims description 3
- 229910052793 cadmium Inorganic materials 0.000 claims description 3
- 244000137852 Petrea volubilis Species 0.000 claims description 2
- 230000001066 destructive effect Effects 0.000 claims description 2
- 239000007789 gas Substances 0.000 claims description 2
- 238000003754 machining Methods 0.000 claims description 2
- 238000002834 transmittance Methods 0.000 abstract description 18
- 230000008901 benefit Effects 0.000 abstract description 3
- 235000012431 wafers Nutrition 0.000 description 69
- 238000011049 filling Methods 0.000 description 9
- 239000000463 material Substances 0.000 description 8
- 239000010935 stainless steel Substances 0.000 description 8
- 238000006243 chemical reaction Methods 0.000 description 7
- 238000001514 detection method Methods 0.000 description 7
- 239000000203 mixture Substances 0.000 description 7
- 238000002360 preparation method Methods 0.000 description 7
- 238000007789 sealing Methods 0.000 description 7
- 238000002791 soaking Methods 0.000 description 7
- 229910001220 stainless steel Inorganic materials 0.000 description 7
- 238000003756 stirring Methods 0.000 description 7
- 238000005303 weighing Methods 0.000 description 7
- 230000005855 radiation Effects 0.000 description 5
- 239000002994 raw material Substances 0.000 description 4
- 239000004065 semiconductor Substances 0.000 description 3
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 description 2
- 239000002904 solvent Substances 0.000 description 2
- 229910052714 tellurium Inorganic materials 0.000 description 2
- 229910001069 Ti alloy Inorganic materials 0.000 description 1
- 239000000969 carrier Substances 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 230000001808 coupling effect Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000002059 diagnostic imaging Methods 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 230000005251 gamma ray Effects 0.000 description 1
- 238000003384 imaging method Methods 0.000 description 1
- 238000007689 inspection Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 230000005658 nuclear physics Effects 0.000 description 1
- 230000005433 particle physics related processes and functions Effects 0.000 description 1
- 230000035755 proliferation Effects 0.000 description 1
- 238000004064 recycling Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 229910001256 stainless steel alloy Inorganic materials 0.000 description 1
- PORWMNRCUJJQNO-UHFFFAOYSA-N tellurium atom Chemical compound [Te] PORWMNRCUJJQNO-UHFFFAOYSA-N 0.000 description 1
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- C—CHEMISTRY; METALLURGY
- C30—CRYSTAL GROWTH
- C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
- C30B29/00—Single crystals or homogeneous polycrystalline material with defined structure characterised by the material or by their shape
- C30B29/10—Inorganic compounds or compositions
- C30B29/46—Sulfur-, selenium- or tellurium-containing compounds
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- C—CHEMISTRY; METALLURGY
- C30—CRYSTAL GROWTH
- C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
- C30B33/00—After-treatment of single crystals or homogeneous polycrystalline material with defined structure
- C30B33/02—Heat treatment
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
- Y02P70/50—Manufacturing or production processes characterised by the final manufactured product
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Abstract
The invention discloses a nondestructive defect control technology of a large-size CdZnTe single crystal. The invention takes a CdZnTe wafer as a processing object; eliminating internal dislocation and amorphous phase precipitation defects by means of liquid phase annealing; the liquid used for liquid phase annealing contains Cd element. The invention can rapidly and effectively improve the infrared transmittance and the resistivity of the wafer by the liquid phase annealing mode, does not cause lattice damage to the surface of the crystal, and realizes the nondestructive defect control of large-size single crystals. The method adopted by the invention is simple to operate, can effectively improve the photoelectric property of the single crystal, and has stronger use value and economic benefit.
Description
Technical Field
The invention relates to a nondestructive defect control technology of a large-size CdZnTe single crystal, in particular to a defect control technology of a CdZnTe single crystal for an X-ray and gamma-ray room temperature detector.
Background
The radiation detection technology has wide application in the fields of space detection, biomedical imaging, high-energy physical research, radioactivity monitoring, homeland security inspection and the like. With the development of nuclear physics and particle physics, semiconductor detectors have been rapidly developed, and compound semiconductor detectors with wide forbidden bands and high average atomic numbers are coming into the line of sight. The CdZnTe detector has excellent radiation detection performance such as high detection efficiency, high energy resolution, room temperature operation and the like, and is the preferred material of the next-generation radiation detector.
High detection efficiency and high energy resolution are the preconditions for the application of the detector in the field of environmental detection and medical imaging. In the CZT crystal growth process, the growth environment is complex and difficult to control due to the coupling effect of a temperature field and a concentration field in the growth process, and the prepared crystal has higher defect density. These defects may introduce certain defect energy levels into the crystal energy band structure, which may affect the carrier lifetime, mobility, etc. transport characteristics for capturing and scattering carriers, and ultimately affect the detection performance of the radiation detector.
Therefore, the industry mainly adopts heat treatment technology to reduce dislocation density and eliminate precipitated phase in batches. However, in the high-temperature heat treatment process, te atoms thermally migrate to cause lattice damage on the surface, so that the crystal quality is affected, and after the tellurium-rich amorphous phase defects are subjected to heat treatment, a large amount of stress dislocation is generated in the surrounding materials of the precipitated phase defects, so that serious dislocation proliferation is formed, and the material performance is reduced to a certain extent. Meanwhile, the heat treatment technology adopted at present has the problems of low efficiency, long time consumption and the like. Therefore, there is a need to develop a new technique for non-destructive defect control to obtain high quality detector grade CZT crystals.
Disclosure of Invention
The invention firstly provides annealing of CdZnTe single crystal in a liquid phase annealing agent and realizes damage-free defect control.
According to the invention, the liquid containing Cd element is used as an annealing medium to realize the nondestructive defect control of CdZnTe monocrystal with the thickness of 3 inches or more, and the infrared transmittance can be effectively improved, the resistivity of the material is improved, and the damage to the surface of the crystal is small by adopting the liquid phase annealing mode.
The invention relates to a nondestructive defect control technology of a large-size CdZnTe single crystal, which takes a CdZnTe wafer as a processing object; eliminating internal dislocation and amorphous phase precipitation defects by means of liquid phase annealing; the liquid used for liquid phase annealing contains Cd element (i.e. the liquid phase annealing agent contains Cd element).
Preferably, the liquid used contains a positive divalent Cd element.
Preferably, the invention relates to a nondestructive defect control technology of a large-size CdZnTe single crystal, wherein the CdZnTe wafer is obtained by machining a tellurium-zinc-cadmium ingot obtained by Bridgman growth.
Preferably, the invention relates to a non-damage defect control technology of a large-size CdZnTe monocrystal, which takes liquid containing at least one of cadmium chloride, cadmium acetate, cadmium sulfate, cadmium nitrate and cadmium sulfide as a liquid-phase annealing agent. The solvent of the liquid phase annealing agent may be water, alcohol, or the like. As a further preferred aspect, the liquid phase annealing agent is a CdCl 2 -containing solution. As a further preferred, the solvent of the solution is water.
Preferably, the invention relates to a nondestructive defect control technology of a large-size CdZnTe single crystal, which comprises the following steps: placing the CdZnTe wafer scratched by the surface cleaner into a container, adding a liquid phase annealing agent, and immersing the CdZnTe wafer by the liquid phase annealing agent; then annealing is carried out at an annealing temperature; obtaining the product.
Preferably, the invention relates to a nondestructive defect control technology of a large-size CdZnTe single crystal, wherein the size of the large-size CdZnTe single crystal is more than or equal to 3 inches.
Preferably, the invention relates to a nondestructive defect control technology of a large-size CdZnTe single crystal, wherein a CdZnTe wafer scratched by a surface cleaner is prepared by the following steps:
Removing the thicker damaged layers on the two sides of the wafer by using sand paper with the size larger than 3000 meshes, and polishing for 30min by using 0.3 mu m aluminum oxide polishing solution and 50nm aluminum oxide polishing solution respectively; polishing until the surface of the sample is bright, and using an ethanol solution for cleaning for many times under 200 times without bright scratches on an optical microscope, and drying with nitrogen for later use.
Preferably, in the technique for controlling the damage-free defects of the large-size CdZnTe single crystal, the mass percentage concentration of CdCl 2 in the liquid-phase annealing agent is about 30-60%, more preferably about 45-55%, and still more preferably about 50%.
Preferably, the invention relates to a nondestructive defect control technology of a large-size CdZnTe monocrystal, and the inner wall of a container is polytetrafluoroethylene. In industrial application, the container used for annealing is a polytetrafluoroethylene lining, and the shell is stainless steel or titanium alloy. The filling factor of the container is 15-80%. When a small number of wafers are processed, a lower fill factor may be selected; when a large number of wafers are processed at a time, the wafers are separated by polytetrafluoroethylene and more liquid phase annealing agent is added, and the filling factor of the container can be adjusted to 50% or more.
Preferably, the invention relates to a nondestructive defect control technology of a large-size CdZnTe single crystal, which comprises the steps of placing a wafer into a container and placing a liquid phase annealing agent; the container is then sealed and placed in a heating device; heating to a set temperature, and preserving heat for a set time at the set temperature; then cooling to room temperature, and taking out the wafer in the protective atmosphere after cooling; and then cleaning with deionized water, and drying with protective gas to obtain a finished product.
In the liquid phase annealing, the heating rate is 1-5 ℃/min, preferably 1-2 ℃/min. The cooling rate is preferably 1-5 deg.C/min, preferably 1-2 deg.C/min.
Preferably, the invention relates to a nondestructive defect control technology of a large-size CdZnTe single crystal, which is characterized in that the temperature is raised to a set temperature, and the temperature is kept for a set time at the set temperature; the set temperature is 50-300 degrees celsius, preferably 60-200 degrees celsius, and more preferably 75-85 degrees celsius. The invention attempts a low-temperature liquid phase annealing technology for the first time.
The invention relates to a nondestructive defect control technology of a large-size CdZnTe monocrystal, when the atom percentage of Zn is 2.5%, the atom percentage of Cd is 47.5% and the atom percentage of Te is 50% in a raw material CdZnTe wafer; in the liquid phase annealing, the temperature is controlled to be 80 ℃ and the time is controlled to be 30 hours; the resistance of the obtained product is more than or equal to 1.0X10 9 Ω & cm, and the infrared transmittance is more than or equal to 50%. With the extension of time, the resistance and infrared transmittance of the product can be further improved, and the requirements of the room-temperature nuclear radiation detector can be completely met.
In industrial applications, annealed CZT wafers are immersed in deionized water to dissolve CdCl 2 crystals on the wafer surface and the wafer is removed after CdCl 2 crystals are completely dissolved. The operation is carried out in a protective atmosphere, deionized and repeated cleaning are carried out for three times, and finally high-pressure nitrogen is used for drying, so that the CZT wafer with the resistivity and the infrared transmittance improved can be obtained.
The method adopted by the invention is simple to operate, can effectively improve the photoelectric property of the crystal, and has stronger use value and economic benefit.
The invention realizes the nondestructive defect control of CdZnTe monocrystal by adopting a Cd 2+ compensation mode, adopts a solution containing Cd 2+ as an annealing source in the liquid phase annealing process, and realizes the annealing and the separation of the wafer in the liquid phase.
The invention has low requirements on the raw material wafer, which can relax the previous process for preparing the raw material wafer, and the invention can apply the raw material wafer to high-value recycling.
Principle and advantages
The invention designs a novel CZT annealing modification technology, which uses a solution containing Cd 2+ (preferably CdCl 2 liquid) as an annealing medium for heat treatment, and characterizes the surface morphology and the photoelectric property of the CZT crystal. After the crystal is annealed in a CdCl 2 liquid-phase environment, the infrared transmittance and the resistivity are improved, and meanwhile, the damage to the surface is small. The infrared transmittance at 400 wave numbers after 30 hours of liquid phase annealing can be increased from 36% to 55%, and the resistivity is increased from 2.35X10 7. Omega. Cm to 1.11X10 9. Omega. Cm. The Zn component of the CdZnTe crystal adopted in the experiment is 2.5 atomic percent, the atomic percent of Cd is 47.5 atomic percent, the atomic percent of Te is 50 atomic percent, the sample is a p-type semiconductor, and the Cd vacancy (V Cd) is the acceptor level in the crystal before annealing, and is obtained by growth by the Bridgman method (provided by new materials of Hunan university Co., ltd.). In the liquid phase environment annealing process, cdCl 2 is heteronuclear at the crystal surface, and the longer the heat treatment time is, the larger the surface crystal size is. The CdCl 2 crystal is adhered to the surface of the crystal and diffuses inwards, and Cd vacancies can enter the crystal through the diffusion of Cd 2+ and are reduced and filled. At the same time, cl - acts as a shallow donor level, whose introduction compensates for acceptor level V Cd in the crystal, causing the fermi level to shift up and the resistivity to be improved.
According to the annealing modification technology based on the CZT crystal material, the CdCl 2 solution is used as a medium for annealing, so that the problem that the quality and the photoelectric energy performance of crystals are reduced after annealing by the existing heat treatment technology is solved, and a new method and guidance are provided for improving the photoelectric performance of the CZT crystal material. The annealed CZT single crystal material has high resistivity and high infrared transmittance; in addition, the process is simple and convenient to operate, the process is mild, the damage to the surface is small, and the current situation that dislocation is greatly proliferated and the surface is seriously damaged after annealing in the past is changed.
Comparison of the photoelectric Properties of the CZT Crystal before and after annealing
The invention realizes the high-efficiency annealing of the CZT crystal under the low-temperature condition for the first time, and greatly improves the performance of the product.
Drawings
FIG. 1 is a graph showing the comparison of the resistivity of CdZnTe crystals before and after annealing, and the bulk resistivity was increased from 2.35X 7 Ω.cm to 1.11X 9 Ω.cm after heat treatment for 30 hours in a CdCl 2 liquid phase environment.
FIG. 2 is a graph showing the comparison of the infrared transmittance of CdZnTe crystals before and after annealing, and it can be seen from the graph that the transmittance of an untreated original sample at 400 wave numbers is about 36%, and the transmittance can reach 55% after annealing for 30 hours in a CdCl 2 liquid phase environment.
Detailed Description
The invention is further illustrated by the following examples of application:
Example 1
1) Pretreatment of a sample: the damaged layers with thicker surfaces were removed from both sides of the wafer with 4000 mesh sandpaper, and each was polished with 0.3 μm alumina polishing solution and 50nm alumina polishing solution for 30min. Polishing until the surface of the sample is bright, and using an ethanol solution for cleaning for many times under 200 times without bright scratches on an optical microscope, and drying with nitrogen for later use.
2) Preparation of annealing medium: weighing cadmium chloride crystal with certain mass, preparing 10mL of 50% solution, and stirring in a magnetic stirrer for 30min to uniformly mix the solution.
3) Annealing container: the inner part of the container used for annealing is a polytetrafluoroethylene lining, the outer shell is stainless steel, and the volume is 25mL.
4) Annealing environment: the wafer was placed in a container, 10mL of cadmium chloride solution was poured into the container, the filling factor of the container was 20%, and the wafer was completely immersed in the liquid phase annealing medium.
5) Liquid phase annealing process: and (3) in the annealing process, sealing the reaction kettle in a muffle furnace, setting a temperature parameter (80 ℃), heating at a speed of 1 ℃/min, preserving heat for 30 hours, and finally cooling to room temperature at a speed of 1 ℃/min.
6) Cleaning: and soaking the annealed CZT wafer in deionized water, dissolving cadmium chloride crystals on the surface of the wafer, and taking out the wafer after the crystals are completely dissolved. The above operations were all carried out in a glove box filled with nitrogen, and then repeatedly washed three times with deionized water, and finally dried with high-pressure nitrogen.
7) The resistance of the CZT wafer can reach 1.11 multiplied by 10 9 ohm cm, and the infrared transmittance can reach 55 percent.
Example 2
1) Pretreatment of a sample: the damaged layers with thicker surfaces were removed from both sides of the wafer with 4000 mesh sandpaper, and each was polished with 0.3 μm alumina polishing solution and 50nm alumina polishing solution for 30min. Polishing until the surface of the sample is bright, and using an ethanol solution for cleaning for many times under 200 times without bright scratches on an optical microscope, and drying with nitrogen for later use.
2) Preparation of annealing medium: weighing cadmium chloride crystal with certain mass, preparing 10mL of cadmium chloride solution with mass fraction of 25%, and stirring in a magnetic stirrer for 30min to uniformly mix the solution.
3) Annealing container: the inner part of the container used for annealing is a polytetrafluoroethylene lining, the outer shell is stainless steel, and the volume is 25mL.
4) Annealing environment: the wafer was placed in a container, 10mL of cadmium acetate solution was poured into the container, the filling factor of the container was 20%, and the wafer was completely immersed in the liquid phase annealing medium.
5) Liquid phase annealing process: and (3) in the annealing process, sealing the reaction kettle in a muffle furnace, setting a temperature parameter (80 ℃), heating at a speed of 1 ℃/min, preserving heat for 30 hours, and finally cooling to room temperature at a speed of 1 ℃/min.
6) Cleaning: and soaking the annealed CZT wafer in deionized water, dissolving CdCl 2 crystals on the surface of the wafer, and taking out the wafer after the CdCl 2 crystals are completely dissolved. The above operations were all carried out in a glove box filled with nitrogen, and then repeatedly washed three times with deionized water, and finally dried with high-pressure nitrogen.
1) The resistance of the CZT wafer can reach 1.09 multiplied by 10 9 ohm cm, and the infrared transmittance can reach 54 percent.
Example 3
1) Pretreatment of a sample: the damaged layers with thicker surfaces were removed from both sides of the wafer with 4000 mesh sandpaper, and each was polished with 0.3 μm alumina polishing solution and 50nm alumina polishing solution for 30min. Polishing until the surface of the sample is bright, and using an ethanol solution for cleaning for many times under 200 times without bright scratches on an optical microscope, and drying with nitrogen for later use.
2) Preparation of annealing medium: weighing cadmium chloride crystal with certain mass, preparing 10mL of cadmium chloride solution with mass fraction of 50%, and stirring in a magnetic stirrer for 30min to uniformly mix the solution.
3) Annealing container: the inner part of the container used for annealing is a polytetrafluoroethylene lining, the outer shell is stainless steel, and the volume is 25mL.
4) Annealing environment: the wafer was placed in a container, 10mL of cadmium chloride solution was poured into the container, the filling factor of the container was 20%, and the wafer was completely immersed in the liquid phase annealing medium.
5) Liquid phase annealing process: and (3) in the annealing process, sealing the reaction kettle in a muffle furnace, setting a temperature parameter (80 ℃), heating at a speed of 1 ℃/min, preserving heat for 20 hours, and finally cooling to room temperature at a speed of 1 ℃/min.
6) Cleaning: and soaking the annealed CZT wafer in deionized water, dissolving CdCl 2 crystals on the surface of the wafer, and taking out the wafer after the CdCl 2 crystals are completely dissolved. The above operations were all carried out in a glove box filled with nitrogen, and then repeatedly washed three times with deionized water, and finally dried with high-pressure nitrogen.
7) The resistance of the CZT wafer can reach 1.10X10 9 Ω cm, and the infrared transmittance can reach 55%.
Example 4
1) Pretreatment of a sample: the damaged layers with thicker surfaces were removed from both sides of the wafer with 4000 mesh sandpaper, and each was polished with 0.3 μm alumina polishing solution and 50nm alumina polishing solution for 30min. Polishing until the surface of the sample is bright, and using an ethanol solution for cleaning for many times under 200 times without bright scratches on an optical microscope, and drying with nitrogen for later use.
2) Preparation of annealing medium: weighing a certain mass of cadmium acetate crystal, preparing 10mL of cadmium acetate solution with the mass fraction of 50%, and stirring for 30min in a magnetic stirrer to uniformly mix the solution.
3) Annealing container: the inner part of the container used for annealing is a polytetrafluoroethylene lining, the outer shell is stainless steel, and the volume is 25mL.
4) Annealing environment: the wafer was placed in a container, 10mL of cadmium acetate solution was poured into the container, the filling factor of the container was 20%, and the wafer was completely immersed in the liquid phase annealing medium.
5) Liquid phase annealing process: and (3) in the annealing process, sealing the reaction kettle in a muffle furnace, setting a temperature parameter (80 ℃), heating at a speed of 1 ℃/min, preserving heat for 30 hours, and finally cooling to room temperature at a speed of 1 ℃/min.
6) Cleaning: and soaking the annealed CZT wafer in deionized water, dissolving the crystal on the surface of the wafer, and taking out the wafer after the crystal is completely dissolved. The above operations were all carried out in a glove box filled with nitrogen, and then repeatedly washed three times with deionized water, and finally dried with high-pressure nitrogen.
7) The resistance of the CZT wafer can reach 1.09 multiplied by 10 9 ohm cm, and the infrared transmittance can reach 54 percent.
Example 5
1) Pretreatment of a sample: the damaged layers with thicker surfaces were removed from both sides of the wafer with 4000 mesh sandpaper, and each was polished with 0.3 μm alumina polishing solution and 50nm alumina polishing solution for 30min. Polishing until the surface of the sample is bright, and using an ethanol solution for cleaning for many times under 200 times without bright scratches on an optical microscope, and drying with nitrogen for later use.
2) Preparation of annealing medium: weighing cadmium sulfate crystal with certain mass, preparing 10mL of cadmium sulfate solution with 50% mass fraction, and stirring in a magnetic stirrer for 30min to uniformly mix the solution.
3) Annealing container: the inner part of the container used for annealing is a polytetrafluoroethylene lining, the outer shell is stainless steel, and the volume is 25mL.
4) Annealing environment: the wafer was placed in a container, 10mL of cadmium sulfate solution was poured into the container, the filling factor of the container was 20%, and the wafer was completely immersed in the liquid phase annealing medium.
5) Liquid phase annealing process: and (3) in the annealing process, sealing the reaction kettle in a muffle furnace, setting a temperature parameter (80 ℃), heating at a speed of 1 ℃/min, preserving heat for 30 hours, and finally cooling to room temperature at a speed of 1 ℃/min.
6) Cleaning: and soaking the annealed CZT wafer in deionized water, dissolving cadmium sulfate crystals on the surface of the wafer, and taking out the wafer after the crystals are completely dissolved. The above operations were all carried out in a glove box filled with nitrogen, and then repeatedly washed three times with deionized water, and finally dried with high-pressure nitrogen.
7) The resistance of the CZT wafer can reach 1.09 multiplied by 10 9 ohm cm, and the infrared transmittance can reach 54 percent.
Example 6
1) Pretreatment of a sample: the damaged layers with thicker surfaces were removed from both sides of the wafer with 4000 mesh sandpaper, and each was polished with 0.3 μm alumina polishing solution and 50nm alumina polishing solution for 30min. Polishing until the surface of the sample is bright, and using an ethanol solution for cleaning for many times under 200 times without bright scratches on an optical microscope, and drying with nitrogen for later use.
2) Preparation of annealing medium: weighing a certain mass of cadmium nitrate crystal, preparing 10mL of cadmium nitrate solution with the mass fraction of 50%, and stirring in a magnetic stirrer for 30min to uniformly mix the solution.
3) Annealing container: the inner part of the container used for annealing is a polytetrafluoroethylene lining, the outer shell is stainless steel, and the volume is 25mL.
4) Annealing environment: the wafer was placed in a container, 10mL of cadmium nitrate solution was poured into the container, the filling factor of the container was 20%, and the wafer was completely immersed in the liquid phase annealing medium.
5) Liquid phase annealing process: and (3) in the annealing process, sealing the reaction kettle in a muffle furnace, setting a temperature parameter (80 ℃), heating at a speed of 1 ℃/min, preserving heat for 30 hours, and finally cooling to room temperature at a speed of 1 ℃/min.
6) Cleaning: and soaking the annealed CZT wafer in deionized water, dissolving cadmium nitrate crystals on the surface of the wafer, and taking out the wafer after the crystals are completely dissolved. The above operations were all carried out in a glove box filled with nitrogen, and then repeatedly washed three times with deionized water, and finally dried with high-pressure nitrogen.
7) The resistance of the CZT wafer can reach 1.06 multiplied by 10 9 Ω & cm, and the infrared transmittance can reach 52 percent.
Example 7
1) Pretreatment of a sample: the damaged layers with thicker surfaces were removed from both sides of the wafer with 4000 mesh sandpaper, and each was polished with 0.3 μm alumina polishing solution and 50nm alumina polishing solution for 30min. Polishing until the surface of the sample is bright, and using an ethanol solution for cleaning for many times under 200 times without bright scratches on an optical microscope, and drying with nitrogen for later use.
2) Preparation of annealing medium: weighing cadmium sulfide crystal with certain mass, preparing 10mL of cadmium sulfide solution with 50% mass fraction, and stirring in a magnetic stirrer for 30min to uniformly mix the solution.
3) Annealing container: the inner part of the container used for annealing is a polytetrafluoroethylene lining, the outer shell is stainless steel, and the volume is 25mL.
4) Annealing environment: the wafer was placed in a container, 10mL of cadmium sulfide solution was poured into the container, the filling factor of the container was 20%, and the wafer was completely immersed in the liquid phase annealing medium.
5) Liquid phase annealing process: and (3) in the annealing process, sealing the reaction kettle in a muffle furnace, setting a temperature parameter (80 ℃), heating at a speed of 1 ℃/min, preserving heat for 30 hours, and finally cooling to room temperature at a speed of 1 ℃/min.
6) Cleaning: and soaking the annealed CZT wafer in deionized water, dissolving cadmium sulfide crystals on the surface of the wafer, and taking out the wafer after the crystals are completely dissolved. The above operations were all carried out in a glove box filled with nitrogen, and then repeatedly washed three times with deionized water, and finally dried with high-pressure nitrogen.
7) The resistance of the CZT wafer can reach 1.08X10 9 Ω cm, and the infrared transmittance can reach 54%.
Claims (9)
1. A non-destructive defect control method for a large-size CdZnTe single crystal is characterized by comprising the following steps of: taking a CdZnTe wafer as a processing object; the liquid containing at least one of cadmium chloride, cadmium acetate, cadmium sulfate, cadmium nitrate and cadmium sulfide is used as a liquid phase annealing agent, and the defects of dislocation and amorphous phase precipitation inside the liquid phase annealing agent are eliminated in a liquid phase annealing mode;
comprising the following steps: placing the wafer in a container, and placing a liquid phase annealing agent; the container is then sealed and placed in a heating device; heating to a set temperature, and preserving heat for a set time at the set temperature; then cooling to room temperature, and taking out the wafer in the protective atmosphere after cooling; then cleaning with deionized water, and drying with protective gas to obtain a finished product; the set temperature is 75-85 ℃.
2. The method for controlling the nondestructive defect of the large-size CdZnTe single crystal according to claim 1, wherein the method comprises the steps of: the CdZnTe wafer is obtained by machining a tellurium-zinc-cadmium ingot which is obtained by the Bridgman method.
3. The technique for controlling the nondestructive defect of the large-size CdZnTe single crystal according to claim 1, wherein: cdCl 2 solution is used as liquid phase annealing agent.
4. The method for controlling the nondestructive defect of the large-size CdZnTe single crystal according to claim 1, wherein the method comprises the steps of: comprising the following steps: placing the CdZnTe wafer scratched by the surface cleaner into a container, adding a liquid phase annealing agent, and immersing the CdZnTe wafer by the liquid phase annealing agent; then annealing is carried out at a set temperature; obtaining the product.
5. The method for controlling the nondestructive defect of the large-size CdZnTe single crystal according to claim 1, wherein the method comprises the steps of: the size of the large-size CdZnTe single crystal is more than or equal to 3 inches.
6. The method for controlling the damage-free defect of the large-size CdZnTe single crystal according to claim 4, wherein the method comprises the following steps: the CdZnTe wafer with surface cleaner scratches was prepared by the following steps:
Removing the thicker damaged layers on the two sides of the wafer by using sand paper with the size larger than 3000 meshes, and polishing 30 min by using an alumina polishing solution with the size of 0.3 mu m and an alumina polishing solution with the size of 50 nm respectively; polishing until the surface of the sample is bright, and using an ethanol solution for cleaning for many times under 200 times without bright scratches on an optical microscope, and drying with nitrogen for later use.
7. The technique for controlling the nondestructive defect of the large-size CdZnTe single crystal according to claim 1, wherein: the mass percentage concentration of CdCl 2 in the liquid phase annealing agent is 30-60%.
8. The method for controlling the nondestructive defect of the large-size CdZnTe single crystal according to claim 1, wherein the method comprises the steps of: the mass percentage concentration of CdCl 2 in the liquid phase annealing agent is 45-55%.
9. The method for controlling the nondestructive defect of the large-size CdZnTe single crystal according to claim 1, wherein the method comprises the steps of: the inner wall of the container is polytetrafluoroethylene.
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