Recent Progress in SiC Monocrystal Growth and Wafer Machining

This paper reviews the development of bulk SiC single crystals grown by sublimation and summarizes their actual status.The thermal field and growth techniques for the growth of SiC crystal are introduced in this paper.The machining technology of large SiC single crystal is also introduced.With the aid of numerical simulation,we have continued to make efforts to optimize the crucible design and the crucible position in the growth system to achieve an accurate distribution of the thermal field.It is found that the use of a low radial temperature gradient leads to a flattening of the crystal interface and therefore to an extended facet with better crystallization.The hardness of the SiC is very close to that of diamond,making it extremely difficult to process large-diameter SiC crystals by cutting,lapping,polishing,etc.Low-warp and low-surface-roughness SiC wafers sliced by a diamond wire saw were obtained.The scratches and damage layer caused by lapping on the SiC wafer surface were reduced by chemo-mechanical polishing (CMP).After CMP,an extremely smooth and low damage layer surface with roughness Ra＜1nm was obtained.