基于异质结理论,提出了一种新型P^+(SiGeC)-n^--n^+异质结功率二极管结构。分析了C对SiGe合金的应变补偿作用的物理机理。利用MEDICI模拟、对比分析了C的引入对器件电特性的影响,并针对不同Ge/C组分比进行优化设计。结果表明:在SiGe/Si功率二极管中加入少量的C,在基本不影响器件正向I-V特性和反向恢复特性的前提下,大大减少了器件的反向漏电流,提高了器件稳定性,而且对于一定的Ge含量存在一个C的临界值,使得二极管具有最小的反向漏电流,该临界值的提出,对研究其它结构SiGeC/Si异质结半导体器件有一定的参考意义。
A novel structure of p^+ (SiGeC)-n^--n^+ heterojunction power diodes is presented based on heterojunction theory. The physical mechanism on strain compensation effects of C for SiGe alloys is analyzed. Using MEDICI, the effects on the device characteristics by incorporation of carbon are simulated and analyzed. Besides, the optimal design is also carried out by adjusting Ge/C ratio in p^+ (SiGeC) layers. The simulation results indicate that the device reverse leakage current and the dependence of its characteristics on critical thickness are reduced largely and the stability is improved because of the incorporating carbon atoms into SiGe/Si diodes, on condition that the forward I-V and reverse recovery characteristics are almost unchanged. Moreover, for certain Ge content there is a critical value of C to achieve the lowest reverse leakage current in SiGeC/Si diodes and this critical value will have some significance for researching on other SiGeC/Si heterojunction semiconductor devices.