2H-SiC体材料电子输运特性的EMC研究

Ensemble Monte Carlo study of electron transport in bulk 2H-SiC

目的 对2H SiC体材料的电子输运特性进行研究。方法 在最新能带结构计算的基础之上,采用非抛物性能带模型和多粒子蒙特卡罗(EnsembleMonteCarlo,EMC)方法。结果 计算表明:低场下,温度一定时,2H SiC纵向电子迁移率比4H SiC和6H SiC都高,横向迁移率则较为接近。296K时,由EMC方法得到的纵向电子饱和漂移速度为2.2×107cm/s,横向电子饱和漂移速度为2.0×107cm/s。当电场条件相同时,2H SiC同4H SiC以及6H SiC中的纵向电子平均能量相差较大。在阶跃电场强度为1000kV/cm时,其横向瞬态速度峰值可达到3.2×107cm/s,反应时间仅为百分之几皮秒量级。结论 可以被用来设计SiC器件和电路。

AimTo study the electron transport properties in 2H-SiC.MethodsIt is disscussed by an Ensemble Monte Carlo technique with an nonparabolic band model from a new ab initio band structures calculation.ResultsThe computation shows that the low field mobility in the C axis direction is higher than 6H-SiC and 4H-SiC. But in the direction perpendicular to the C axis,the mobilities are comparable. At 296 K,the peak saturation velocities given by the model are 2.2×10~7cm/s and 2.0×10~7cm/s when the electric field is applied parallel and perpendicular to the C axis respectively. The difference in mean energy for E‖C among these three kinds of α-SiC is large. The peak transient velocity for E⊥C at high electric field pulse such as 1 000 kV/cm is 3.2×10~7 cm/s. The response time is only in deep subpicoseconds.Conclusion The results can be used to design SiC device and circuit.