4H-SiC雪崩光电探测器中倍增层参数的优化模拟

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

应用ATLAS模拟软件,设计了吸收层与倍增层分离的(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9.0×10^(17)cm^(-3)。模拟分析了该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-66.4 V下可获得较高的倍增因子10~5;在0 V偏压下峰值响应波长(250 nm)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1.5×10~3;其归一化探测率最大可达1.5×10^(16)cmHz^(1/2)W^(-1)。结果显示该APD具有较好的紫外探测性能。

A separate absorption and multiplication （SAM） 4H-SiC avalanche photodiode（APD） was de- signed by using the simulation software of ATLAS. The influences of various thicknesses and doping concen- trations 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 ×10^17 cm-3 for multiplication layer were obtained. The simulation results showed that the APD exhibited low break- down voltage of -66.4 V with high gain of 105. At the bias of 0 V, 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 ×10^3 close to the breakdown voltage and the maximum spectral detectivity about 1.5 ×10^16 cmHz1/2w-1 were also achieved. The above results indicated that the APD had a good performance for UV signal detection.