Effects of Grain Size of Source Material on Growing 6H-SiC Bulk Crystal by Physical Vapor Transport

Abstract

In this article, effects of grain size of source material on growing 6H-SiC bulk single crystal by physical vapor transport (PVT) have been studied by observing the experimental results using source materials of different grain sizes through optical microscope and calculative analysis and discussions. The results indicate that source materials with different grain sizes affect the growth process of SiC bulk single crystal by PVT mainly from three perspectives, i.e., the effective heat-transfer coefficient of the source material, the supersaturation, and the ratio of Si/C in the growth crucible on the basis of other parameters. Furthermore, a proposed way to improve the quality of 6H-SiC bulk single crystal is optimizing the grain size of the source material, and the optimum grain size for sublimation growth of 6H-SiC bulk crystal in our lab is 120 µm.

Keywords:

• Bulk crystal
• Grain size
• Physical vapor transport
• Single crystal
• Source material
• 6H-SiC

Notes

Here K _g refers to the modified gas thermal conductivity, K _b the effective thermal conductivity of the packed source materials, K _r the effective radiation conductivity of the packed raw materials, K _eff the total effective heat-transport coefficient, K _eff  = K _b  + K _r .