SAGCM-APD增益影响因子分析与优化

Optimization and analysis on impact factors of SAGCM-APD gain

应用二维漂移扩散模型研究具有分立吸收层、渐变层、电荷层和倍增层结构(SAGCM)的InGaAsP蛳InP雪崩光电探测器(APD),仿真分析了不同电荷层、倍增层厚度和掺杂浓度对电场分布、电流响应及击穿电压的影响,特别是参数变量对增益计算模型的影响,载流子传输过程的时间依赖关系和倍增层中所处位置的影响。仿真结果表明:较高掺杂浓度和较薄电荷层结构可以改变器件内部的电场分布,进而提高增益值。当入射光波长为1.55μm,光功率为500 W/m2时,光电流响应量级在10-2 A;阈值电压降低到10 V以下,击穿电压为42.6 V时,器件倍增增益值大于100。

The avalanche photodiode（APD）,which was comprised of separate layer of absorption,grading,charge and multiplication（SAGCM） had been studied,and the impact of gain parameter was presented in detail by two-dimensional drift diffusion model.The influence of different thicknesses and doping concentration of both the charge and multiplication layers on electric field distribution,currentvoltage characteristic and breakdown voltage were simulated and analyzed,especially the impact of parameters on gain calculation model,influences of the carriers vs.time in transfer process and in the position of multiplication layer.Simulation results show that when threshold voltage drops to 10 V and breakdown voltage is about 42.6 V,the device still has a good multiplication gain.The result further shows the better electrical field distribution and current response can be achieved with higher doping concentration and thinner charge layer,which can improve the multiplication gain.