Method for preparing large-size CVD (Chemical Vapor Deposition) diamond crystal

Abstract

The invention discloses a method for preparing a large-size CVD (Chemical Vapor Deposition) diamond crystal. The method comprises the following steps: (1) cutting a single diamond crystal grown by using an HPHT (High Temperature and High Pressure) method so as to obtain single HPHT diamond crystal sheets; (2) carrying out surface cleaning; (3) throwing a photoresist to the single HPHT diamond crystal sheets, and carrying out membrane hardening so as to obtain design patterns; (4) depositing a medium membrane by using a CVD method; (5) removing the photoresist and the medium membrane outside the design patterns so as to obtain design medium membrane patterns; (6) splicing the single HPHT diamond crystal sheets in CVD equipment, and carrying out plasma etching so as to obtain a new surface;(7) growing a thick-layer CVD single diamond crystal on the new surface by using a microwave plasma chemical vapor deposition method; (8) cutting and removing the spliced single HPHT diamond crystal sheets, thereby obtaining the self-supported large-size CVD diamond crystal. By adopting the method, growth defects at crystal boundaries and parts nearby of spliced single diamond crystals grown by using the CVD method can be avoided, the quality of the crystal can be ensured, and the self-supported large-size CVD diamond crystal can be prepared.

Description

technical field [0001] The invention relates to a method for preparing a large-size, low-defect diamond wafer, belonging to the technical field of crystal growth. Background technique [0002] Diamond wafer preparation mainly includes high temperature and high pressure method (HPHT) and microwave plasma chemical vapor deposition (MPCVD). Synthesizing diamond by HPHT requires the use of a metal catalyst, and its atoms will inevitably penetrate into the diamond crystal and exist in the form of impurities, which will affect its purity. At present, the maximum size of large-grain diamond single crystal wafers grown by high-temperature and high-pressure methods has reached more than 10 mm, which is still far from the requirements of semiconductor epitaxy. However, high-quality diamond single crystals grown by MPCVD can be completely colorless and transparent, with almost no impurities. At present, the maximum size of CVD diamond has reached 12.5mm, and mosaic splicing has reach...

AI Technical Summary

Problems solved by technology

[0007] The present invention provides a method for preparing large-size CVD diamond crystals. The CVD method is used to grow large-size diamond crystals on spliced ​​HPHT diamond single wafers, so as to solve the problem of using CVD to grow diamonds in the prior art to easily form polycrystals at the splicing seams and problems with poor crystal quality

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