说明：  本人主要学习研究synopsis公司的Sentaurus TCAD半导体工艺软件的使用,此程序主要是实现对光电二极管的I-V特性曲线的仿真脚本（可以测试反相击穿电压以及正向阈值电压）
(I mainly study the synopsis of Sentaurus TCAD semiconductor process software, the use of this program is mainly for the photodiode I- V characteristic curve of the simulation script (can test the reverse breakdown voltage, and positive threshold voltage))