InGaAs/InP单光子雪崩光电二极管InP顶层掺杂研究

InP cap layer doping density in InGaAs/InP single-photon avalanche diode

通过理论计算和对比实验研究了InGaAs/InP单光子雪崩光电二极管中InP顶层掺杂浓度对于器件性能的影响.理论结果显示,InP顶层的掺杂浓度越低越有利于抑制边缘击穿,降低隧穿暗载流子产生速率,提高雪崩击穿几率.实验结果显示,顶层非故意掺杂的器件在223K下获得了20%的单光子探测效率和1kHz的暗计数率,其单光子探测效率比顶层掺杂浓度为5×10^(15)/cm^3的器件高3%~8%,而暗计数率低一个量级.结果表明,降低InP顶层的掺杂浓度有利于提高器件性能.

The influence of the InP cap layer doping density of InGaAs/InP SPAD was studied through theoretical calculation and comparative experiment. Theoretical results show that low cap layer doping density is beneficial to suppress premature edge breakdown, reduce tunneling carrier generation rate, and increase breakdown probability. Experimental results show that devices with unintentionally doped cap layer have achieved 20% single photon detection efficiency and 1 kHz dark count rate at 223 K. Compared with devices with cap layer doping density of 5×10^15/cm^3 , the single photon detection effi- ciency increases by 3% -8%, and the dark count rate decreases by about an order of magnitude. It is demonstrated that reducing the cap layer doping density is beneficial to improve the performance of In- GaAs/InP SPAD.