【摘要】 回顾了SiC单晶的发展历史,总结了目前的发展状况,同时介绍了SiC单晶生长所需要的温场和生长工艺,最后介绍了SiC单晶的加工技术.通过模拟计算与具体实验相结合的方法,调整坩埚在系统中的位置及优化坩埚设计可以得到理想温场.近平微凸的温场有利于晶体小面的扩展,进而有利于减少缺陷提高晶体的质量.由于SiC硬度非常高,对单晶后续的加工造成很多困难,包括切割和磨抛.研究发现利用金刚石线锯切割大尺寸SiC晶体,可以得到低翘曲度、低表面粗糙度的晶片;采用化学机械抛光法,可以有效地去除SiC表面的划痕和研磨引入的加工变质层,加工后的SiC晶片粗糙度可小于1nm.更多还原

【Abstract】 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.更多还原