中文摘要：

将新器件结构与新型半导体材料相结合，提出了一种新型的n^-区三层渐变掺杂理想欧姆接触型P^＋（SiGeC）-n^- -n^＋异质结功率二极管，并对n区的杂质分布梯度进行了优化．基于MEDICI，给出了该结构的关键物理参数模型，并在此基础上对新结构的设计思路和工作原理进行了全面分析．结果表明，与常规理想欧姆接触结构相比，该新结构在保持快而软反向恢复特性的前提下，反向阻断电压增加了近一倍，而且正向通态特性也有所改善，很好地实现了功率二极管中Qs-Vf-Ir三者的良好折中．

英文摘要：

A novel structure of ideal ohmic contact p^＋ （SiGeC）-n^- -n^＋ diodes with three-step graded doping concentration in the base region is presented, and the changing doping concentration gradient is also optimized. Using MEDICI, the physical parameter models applicable for SiGeC/Si heterojunction power diodes are given. The simulation results indicate that the diodes with graded doping concentration in the base region not only have the merit of fast and soft reverse recovery but also double reverse blocking voltage,and their forward conducting voltage has dropped to some extent,compared to the diodes with constant doping concentration in the base region. The new structure achieves a good trade-off in Qs-Vf-Ir ,and its combination of properties is superior to ideal ohmic contact diodes and conventional diodes.