生长气体流量对SiC单晶缺陷的影响

实现了熔融KOH进行SiC体单晶择优腐蚀估测缺陷密度的方法.本文报道了采用该技术对体SiC单晶缺陷密度估测的结果.腐蚀会在Si面形成六边形腐蚀坑,在C面形成圆形腐蚀坑.腐蚀速率和蚀坑形状与SiC生长工艺有关.对在高生长气流量下用PVT工艺制备的SiC样品,其刃位错、螺位错与微管密度分别为2.82×105,94和38cm-2;对在低生长气流量下用PVT工艺制备的SiC样品,其上述缺陷密度分别为9.34×105,2和29cm-2.结果表明:随着生长气体流量的增加,由于避免了N2掺杂,刃位错密度下降.

Effect of Growth Gas Flow Rate on the Defects Density of SiC Single Crystal

A method for estimating the defects density in SiC bulk crystals by defect-selective etching in molten KOH hasalready been successfully demonstrated. In this paper, the results of applying this technique to bulk SiC crystals are repor-ted. Etching produced hexagonal pits on the Si-polar (0001) plane,while round pits formed on the C face. The etching rateand the nature of etch pits for SiC depends on the growth process. For SiC crystals grown by the PVT process with highgrowth gas flow rate, the edge and screw dislocation density and the MP density are about 2.82×105 , 94, and 38cm-2, re-spectively. For SiC crystals grown by the PVT process with low growth gas flow rate, those defects densities are about 9.34×105 ,2, and 29cm-2 ,respectively. The results indicate that as the growth gas flow rate increases, the edge dislocationdensity decreases to avoid N2 impurity.