4H-SiC 雪崩光电探测器中倍增层参数的优化模拟

应用ATLAS模拟软件，设计了吸收层和倍增层分离的（SAM）4H-SiC 雪崩光电探测器（APD）结构。分析了不同外延层厚度和掺杂浓度对器件光谱响应的影响，对倍增层参数进行优化模拟，得出倍增层的最优化厚度为0.26μm，掺杂浓度为9.0×1017cm^-3。模拟分析了APD的反向IV特性、光增益、不同偏压下的光谱响应和探测率等，结果显示该APD在较低的击穿电压66.4V下可获得较高的倍增因子105；在0V偏压下峰值响应波长（250nm）处的响应度为0.11A/W，相应的量子效率为58%；临近击穿电压时，紫外可见比仍可达1.5×103；其归一化探测率最大可达1.5×1016cmHz ^1/2 W^-1。结果显示该APD具有较好的紫外探测性能。

Optimal simulation of parameters for multiplication layer of 4H-SiC avalanche photodiode

A separate absorption and multiplication (SAM) 4H-SiC avalanche photodiode(APD) was designed by using the simulated software of ATLAS. The influences of various thicknesses and doping concentrations of epitaxial layers on spectral response were analysed, and the parameters of multiplication layer were optimal simulated, then the optimal thickness of 0.26 μm and doping concentration of 9.0×1017 cm-3 for multiplication layer were obtained. The simulation results showed that the APD exhibited low breakdown voltage of 66.4 V with high gain of 105. At the bias of 0V, the peak responsivity was about 0.11 A/W and the corresponding quantum efficiency was 58%. The UV-to-visible rejection ratio of 1.5×103 close to the breakdown voltage and the maximum spectral detectivity about 1.5×1016 cmHz1/2W-1 were also achieved. The above results indicated that the APD had a good performance for UV signal detection.