回熔过程对HgCdTe长波红外光伏探测器的I-V性能的影响

对三种不同工艺的HgCdTe长波器件(标准工艺、回熔处理、离子注入后退火)的I-V性能分别进行测试,并通过理论计算与实验数据拟合提取上述器件参数,分析暗电流机制及导致暗电流变化的原因。文章中使用的暗电流机制的模型由扩散电流、产生-复合电流、缺陷辅助隧道电流和直接隧道电流组成。从拟合得到的器件参数中可以发现回熔过程中产生了大量的缺陷,导致缺陷辅助隧道电流、产生复合电流显著增加,器件反偏电阻减小,I-V性能变差。与离子注入后退火器件的性能变化相比,推测导致器件回熔后性能下降的原因是ZnS钝化层受热不稳定。

Effect of the reflowing process on the I-V characteristics of LWIR HgCdTe photovoltaic detector

The I-V characteristics of the long-wavelength infrared HgCdTe photovoltaic devices fabricated by different process including standard process, reflowing process and post-implantation annealing process were measured and investigated by model fitting analysis. This model includes four current components, such as diffusion current, generation-recombination current, band-to-band tunneling current and trap-assistant tunneling current. From the model fitting analysis, the trap concentration increased dominantly during the reflowing process, which led the the trap-assistant tunneling current and the g-r current increased largely. The reverse bias resistance dropped a lot and the performance of the device degraded. Compared to the performance of the post-implantation annealed device, it is presumed that the reason which led to the degradation of the performance of the reflowed device is the instability of the ZnS passivation layer.