4H-SiC基超结器件各向异性的TCAD建模分析

TCAD Modeling of Anisotropy 4H-SiC Superjunction Devices

基于文献报道的4H-SiC材料的各向异性物理特性,首次提出4H-SiC基超结器件的各向异性物理模型,并对不同晶向的碰撞电离分别进行考虑。基于该模型,我们对(0001)和(1120)两种晶向晶圆的4H-SiC超结器件的电学特性进行了研究。与(1120)晶圆相比,(0001)晶圆的碰撞电离系数较小,可以实现更高的击穿电压VB。由于碰撞电离各向异性,与传统4H-Si C基器件相比,超结器件的二维电场分布可以将(1120)晶圆器件的击穿电压VB从(0001)晶圆器件的60%提高到72%。

Based on reported experimental physical properties of anisotropic 4H-SiC,physical models of anisotropic 4H-Silicon carbide（4H-SiC）have been proposed first time for superjunction（SJ）devices. Anisotropic impact ioniza-tion is also considered in this model. Using proposed model,we investigated the electrical properties of anisotropic 4H-SiC SJ devices with respect to wafer orientation（0001）and（1120）. Compared to the conventional anisotropic 4H-SiC devices,the breakdown voltage（VB）of（1120）SJ devices is increased to72% of（0001）wafer devices from 60%due to the bidirectional electric field profile.