Method and system for splicing and growing single-crystal diamond

Abstract

The invention belongs to the technical field of diamond preparation and discloses a method and a system for splicing and growing single-crystal diamonds. The method comprises the following steps: putting a seed crystal into a plasma CVD equipment cavity, sucking off ultimate pressure, introducing hydrogen, inputting energy, generating power discharge, and adjusting the temperature of the seed crystal; introducing a methane (or carbon-containing gases such as acetone and carbon dioxide) gas, growing the seed crystal for 1-100 hours at 800-1000 DEG C, and the like. According to the method, single-crystal diamonds are grown by using a CVD method through spicing growth, the purpose that the single-crystal diamonds is grown in a large scale is achieved, synthesis sizes directly depend on sizesof the seed crystals since conventional growth of single-crystal diamonds can be only longitudinally amplified on original seed crystals, two single-crystal diamond flakes of a same size and approximate thicknesses are fixed and spliced and grown simultaneously, then a large-size single-crystal diamond is grown, and bottle neck problems are solved.

Description

technical field [0001] The invention belongs to the technical field of diamond preparation, in particular to a method and system for splicing and growing single crystal diamond. Background technique [0002] At present, the synthesis of single crystal diamond is limited by its size. Usually, a single natural diamond or artificially synthesized single crystal diamond flake is used as a seed crystal to grow on its original size. Because large-size single crystal diamond is rare and expensive, it is synthesized Diamond is limited by the size of the seed crystal. Since there are many defects at the edge of the seed crystal and it is difficult to control and it is easy to grow polycrystalline diamond, the size of the obtained product will not be larger than the size of the original seed crystal, so large-sized single crystal diamond cannot be obtained. [0003] In summary, the problems in the prior art are: [0004] The existing process only grows laterally on the surface of a s...

AI Technical Summary

Problems solved by technology

[0004] The existing process only grows laterally on the surface of a single seed crystal, but this method is difficult (requires precise control of growth parameters, and the fluctuation area is small), high cost (requires high-configuration deposition equipment to achieve), and the actual effect is not obvious ( The enlarged size does not exceed 1mm, and the four corners of the seed crystal cannot grow due to orientation restrictions)

The specific problems are as follows: first; because the edge of the seed crystal will produce "edge effect" to cause edge discharge, which will cause the aggregation of active groups at the edge of the seed crystal, and induce non-diamond impurities and The generation of polycrystalline structure leads to the expansion of polycrystalline diamond, and finally further reduces the size of single crystal diamond; second, because the lateral growth rate is slower, usually half of the vertical growth rate, the lateral area will increase with the increase of the vertical area , the grown product is not a complete block material, but a trapezoidal product with a narrow bottom and a wide top. After cutting and polishing, a large-area product cannot be obtained; third, due to the limitation of crystal orientation, the growth of single crystal diamond will be along the 100 direction, and the directions of the four corners of the seed crystal are all 111 orientations. During the growth process, they will only grow along the 100 direction, while the four corners of the 111 directions do not grow single crystals but impurity defects, not overall growth.

In summary, the existing technology cannot solve the fundamental problem of growing large-size single crystal diamond

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