Apparatus for vertical pulling growth of CdZnTe monocrystals, and method thereof

Abstract

The invention discloses an apparatus for the vertical pulling growth of CdZnTe monocrystals, and a method thereof. The apparatus comprises a tubular furnace body, a quartz ampoule and a graphite boat, the furnace body comprises synthetic furnaces, buffer furnaces, inclined plane furnaces and Cd source furnaces, the quartz ampoule is arranged in the furnace body, the graphite boat is arranged in the quartz ampoule. The method for the vertical pulling growth of CdZnTe monocrystals through adopting the apparatus generally comprises the following steps: uniformly putting a high-purity Te raw material, a high-purity Zn raw material and a high-purity Cd raw material in the graphite boat according to synthetic proportions, putting a small amount of Cd at the bottom of the quartz ampoule, slowly putting the graphite boat on the baffle board of the quartz ampoule, carrying out vacuumizing tube sealing, putting the quartz ampoule in the tubular furnace body to make the graphite boat in the middle of the synthetic furnaces, controlling conditions for synthesizing polycrystals, controlling the temperature distribution of the furnace body, slowly upward moving the furnace body until crystallization finishing, and carrying out vertical pulling growth to obtain the CdZnTe monocrystals. According to the invention, CdZnTe polycrystals are synthesized without using other rocking furnaces; and the obtained CdZnTe monocrystals have the advantages of uniform crystal ingot component, less twin crystals, and less Te precipitation or inclusions.

Description

technical field [0001] The invention relates to a device and method for vertically pulling and growing cadmium zinc telluride single crystal, especially suitable for preparing cadmium zinc telluride single crystal or similar compound single crystal with high melting point, multi-component, volatile and low thermal conductivity. Background technique [0002] The room temperature CdZnTe nuclear radiation detector has the irreplaceable technical advantages of sodium iodide scintillators and germanium semiconductor detectors, making it a research hotspot in medical imaging, hard X-rays, and high-energy gamma-ray astronomical applications in recent years. In particular, it has unique technical advantages in the high energy resolution of cosmic hard X-ray radiation and the spatial resolution of the fabricated focal plane devices. [0003] High-resistivity, large-area CdZnTe single crystal material is the basis for the preparation of nuclear radiation detectors. However, due to the...

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Problems solved by technology

[0003] High-resistivity, large-area CdZnTe single crystal material is the basis for the preparation of nuclear radiation detectors. However, due to the limitations of the preparation process and the physical properties of the material itself, a large amount of cadmium is commonly present in the CdZnTe single crystal prepared at present. Defects such as vacancies and twins seriously affect the quality of the crystal ingot, reduce the yield of single wafers, increase the manufacturing cost of devices, and restrict the development of CdZnTe devices

For example, due to the low thermal conductivity of CdZnTe, the solid-liquid interface of the current vertical Bridgman method protrudes deeply into the solid phase, and there are a large number of twins in the grown ingot, which is difficult to cut single chip

Different from the technology for preparing CdZnTe single crystal by vertical Bridgman method, the patent (authorization number: CN101210346B) proposes a device and technology for growing CdZnTe single crystal by melting in the horizontal zone, which indeed improves the quality of the crystal ingot. It is especially suitable for the growth of high-purity crystals. However, this method has the problem that the melt surface is too large, and the gas phase growth is serious, resulting in a large change in the composition of the crystal ingot axis.

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