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CN-122013298-A - Preparation method of multi-element compound semiconductor crystal

CN122013298ACN 122013298 ACN122013298 ACN 122013298ACN-122013298-A

Abstract

The invention relates to the field of II-VI group compound semiconductor material preparation, and discloses a preparation method of a multi-element compound semiconductor crystal, wherein the multi-element compound semiconductor crystal is selenium tellurium magnesium cadmium crystal, the chemical formula is Cd 0.95 Mg 0.05 Te 1‑x Se x , the preparation method sequentially comprises the steps of synthesizing selenium tellurium magnesium cadmium polycrystal material by a high-temperature melting method, carrying out crystal growth by a vertical Bridgman method and carrying out In-situ annealing treatment, and the preparation raw material comprises Cd, mg, te, se basic raw material In proportion according to the stoichiometric ratio of Cd 0.95 Mg 0.05 Te 1‑x Se x , and is added with excessive Te and doped with In element. By adopting a three-temperature-zone crystal growth furnace and combining a vertical Bridgman method to grow selenium-tellurium-magnesium-cadmium single crystals, the precise regulation and control of the temperature gradient can be realized, a flatter solid-liquid interface can be formed, the generation of defects such as dislocation, twin crystals and inclusion in the crystals can be effectively reduced, meanwhile, the thermal stress in the crystal growth process is reduced, and the mechanical stability of the crystals is improved.

Inventors

  • YU PENGFEI
  • ZHANG TONG
  • YANG GUIZHI
  • GUO JIASAI
  • SUN GUODONG

Assignees

  • 长安大学

Dates

Publication Date
20260512
Application Date
20260317

Claims (9)

  1. 1. A preparation method of a multi-element compound semiconductor crystal is characterized in that the multi-element compound semiconductor crystal is selenium tellurium magnesium cadmium crystal, the chemical formula is Cd 0.95 Mg 0.05 Te 1-x Se x , and the preparation method sequentially comprises the steps of synthesizing selenium tellurium magnesium cadmium polycrystal material by a high-temperature melting method, carrying out crystal growth by a vertical Bridgman method and carrying out in-situ annealing treatment; the preparation raw materials comprise Cd, mg, te, se basic raw materials which are mixed according to the stoichiometric ratio of Cd 0.95 Mg 0.05 Te 1-x Se x , excessive Te is added on the basis of the basic raw materials, and In element is doped; The crystal growth adopts a three-temperature-zone crystal growth furnace, the temperature of a high temperature zone of the three-temperature-zone crystal growth furnace is 1110-1140 ℃, the temperature of a medium temperature zone is 1060-1090 ℃, the temperature of a low temperature zone is 750-800 ℃, and the crucible descending rate in the crystal growth process is 0.5-1mm/h.
  2. 2. The method for producing a multi-element compound semiconductor crystal according to claim 1, wherein an atomic content of Se in Cd 0.95 Mg 0.05 Te 1-x Se x is 0 to 4at%, and a temperature gradient of the three-temperature zone crystal growth furnace is 10 to 15K/cm.
  3. 3. The method for producing a multi-element compound semiconductor crystal according to claim 1, wherein the molar fraction of the excess Te is 0.5%, and the doping volume concentration of the In element is 10ppm.
  4. 4. The method for producing a multi-element compound semiconductor crystal according to claim 1, wherein the high-temperature melting method has the process parameters of vacuum degree (5-6) × -5 Pa, melting temperature 1100-1150 ℃ and heat-retaining period of 48 hours.
  5. 5. The method for producing a multi-element compound semiconductor crystal according to claim 1, wherein the Cd, mg, te, se raw materials each have a purity of 5N to 7N, the In element has a raw material purity of 7N, and the crucible used for producing the multi-element compound semiconductor crystal is a 6N high-purity quartz crucible coated with a carbon film.
  6. 6. The method for preparing a multi-element compound semiconductor crystal according to claim 1, wherein the crystal growth specific process of the vertical Bridgman method is that the three temperature areas are heated to a set temperature for 10-20 hours, then the temperature is kept for 12-16 hours to enable the polycrystalline material to be completely melted, the crucible is lowered and simultaneously rotated, and the total crystal growth duration is 110-220 hours.
  7. 7. The method for preparing a multi-element compound semiconductor crystal according to claim 1, wherein the in-situ annealing treatment has the technological parameters of 500 ℃ annealing temperature and 120-240h annealing time, and the power supply of a growth furnace is turned off after the annealing is completed, and the crystal is cooled to room temperature along with the furnace.
  8. 8. The method for producing a multi-component compound semiconductor crystal according to claim 1, wherein the specific steps of synthesizing a polycrystalline material by a high-temperature melting method are as follows: filling all the proportioned raw materials into a quartz crucible, vacuumizing to a set vacuum degree by adopting a molecular pump, and sealing the quartz crucible in a melting way; And (3) putting the crucible after the melting and sealing into a swinging furnace, firstly degassing at a low temperature for 12-16 hours, then heating to a melting temperature in a gradient way, preserving heat, periodically swinging the crucible to promote the convection of the melt, and finally cooling to room temperature along with the furnace to obtain the polycrystal material.
  9. 9. The method for producing a multi-element compound semiconductor crystal according to claim 1, wherein the crystal is a selenium tellurium magnesium cadmium single crystal having a crystal diameter of not less than 30mm and a resistivity of not less than The microhardness is not lower than 0.41GPa, and the infrared transmittance is not lower than 60%.

Description

Preparation method of multi-element compound semiconductor crystal Technical Field The invention relates to the field of preparation of II-VI compound semiconductor materials, in particular to a preparation method of a multi-component compound semiconductor crystal. Background The room temperature radiation detector has irreplaceable application value in the key fields of national economy and national safety such as medical imaging, safety inspection, nuclear safety monitoring, industrial nondestructive detection and the like, and the working performance of the room temperature radiation detector directly depends on the physicochemical and electrical characteristics of a core semiconductor material. The II-VI compound semiconductor crystal is a preferable material for preparing the room temperature radiation detector because of the characteristics of moderate forbidden bandwidth, high volume resistivity, large radiation absorption coefficient, excellent carrier mobility life product and the like, and the detector prepared from the material does not need low-temperature refrigeration equipment and has the advantages of small specific volume, low power consumption, high detection efficiency and the like, so that the research and development of the preparation technology of the related crystal material are always the research focus of the field of semiconductor materials. Among the numerous II-VI compound semiconductor crystals, tellurium-magnesium-cadmium (CdMgTe) crystals become an important research direction of materials for room temperature radiation detectors by virtue of high density, high effective mass, high resistivity and excellent electron transport performance, but the materials still have a plurality of problems to be solved in the practical preparation and application processes, such as low intrinsic hardness of the crystals, easy breakage in the processing and use processes, easy formation of dislocation, twin crystal and other structural defects in the crystal growth process, and meanwhile, the formation and aggregation of Te vacancy, cd vacancy and other intrinsic defects and Te inclusion phases can seriously influence the component uniformity and electrical properties of the crystals, thereby limiting the application of the crystals in high-performance detectors. The research shows that by introducing a small amount of Se elements into the CdTe-based ternary compound semiconductor, the overall hardness of the crystal can be improved through the solid solution hardening effect, meanwhile, the segregation coefficient of the Se elements approaches to 1, the component uniformity of the crystal in the axial direction and the radial direction can be effectively improved, and the formation of intrinsic defects and inclusion phases can be inhibited, so that the Se-Te-Mg-Cd ternary compound semiconductor crystal becomes a potential room temperature radiation detector material with high hardness and excellent electrical properties, and is widely paid attention to in the industry. At present, the preparation of CdTe-based compound semiconductor crystal adopts the vertical Bridgman method, the method is a mainstream crystal growth technology because of simple process principle and large-size crystal growth, but the prior art adopts two-temperature-zone crystal growth furnaces to implement the method, the two-temperature-zone furnaces only consist of a high-temperature zone and a low-temperature zone, the temperature gradient adjusting space is limited, precise adjustment and control are difficult to realize, a curved solid-liquid interface is easy to form, defects such as dislocation and twin crystals in the crystal are increased, the generation probability of crystal cracks is greatly improved due to excessive thermal stress, and meanwhile, the fixed temperature gradient is easy to cause segregation of crystal components, uneven element distribution and the overall quality of the crystal are reduced. In addition, in the existing preparation process of CdTe-based crystals, the synthesis and the crystal growth of the polycrystalline materials are usually completed in different equipment or different crucibles, the raw materials are extremely easy to be polluted by environment or appliances in the transfer process, impurity defects are introduced to further deteriorate the physicochemical properties of the crystals, while the partial preparation process attempts to integrate the synthesis and the crystal growth of the polycrystalline materials, but the parameter setting of the process steps lacks the cooperativity, the links are not smoothly connected, no targeted post-treatment process is arranged, the residual stress and microscopic defects in the crystals cannot be effectively eliminated, and the high-quality monocrystalline materials are difficult to prepare. On the other hand, the existing preparation technology of the CdTe-based multielement compound semiconductor crystal also has the problems of co