掺氮6H-SiC单晶的电阻率、迁移率及自由载流子浓度

测试了国产和美国Cree公司生产的n型6H-SiC低温下的电学参数,包括电阻率、迁移率和自由载流子浓度,并用FCCS软件数据拟合分析得到两种SiC的杂质浓度和能级.实验结果表明:杂质浓度和补偿度对低温下SiC的电性能有很大影响,轻度补偿的掺氮6H-SiC是施主氮的两个能级共同起作用;而重度补偿的6H-SiC在低温时则是受主能级起作用,并且后者迁移率随温度变化曲线的峰值降低并右移.同时发现重度补偿的SiC在较低温度时由n型转变成了p型,并从理论上分析了产生这种现象的原因.

Resistivity,Mobility,and Free Carrier Concentration of 6H-SiC Crystal Doped by Nitrogen

Electric parameters including resistivity,mobility,and free carrier concentration are measured at low temperatures for n-type 6H-SiC from China and Cree corporation.Their impurity concentration and levels are obtained from the fitting data of FCCS.The experimental results show that the concentration and compensation level of the impurity greatly affect the electric properties of SiC at low temperatures.The two different levels of nitrogen donor work together for 6H-SiC with a low compensation,but the accepter levels work at low temperatures for 6H-SiC with a high compensation.The peak of the mobility curve of the latter decreases and moves to the right as temperature increases.At the same time,the highly compensated SiC is transformed from n-type to p-type at low temperatures,which is analyzed theoretically.