If the impact ionization occurs in a region of high electrical field then it can result in avalanche multiplication of carriers. This process is used in avalanche photodiodes enabling individual photons to be detected when the incident flux of light is very low. HgCdTe is an almost ideal material for avalanche photodiodes, however to achieve the highest performance in near-room temperatures, a careful design of device structure is needed, to reach the highest performance in near-room temperatures. N⁺-ν-p-P⁺ photodiode meets the requirements of the separated absorption and multiplication regions. This paper describes the results of research aimed at investigation of the impact ionization mechanism in HgCdTe N⁺-ν-p-P⁺ photodiode optimized for 8 μm cut-off wavelength at 230 K. The results show that the parameters of the ν-region greatly influenced on the distribution of the electric field and the generation rate due to the impact ionization. In addition, ν-region has the effect on reduction of undesirable tunneling in the space charge region. For this purpose, it is necessary to keep the doping in this region as low as possible and to extend the energy gap in relation to the absorbing region.

如果碰撞电离发生在高电场区域，则可能导致载流子雪崩倍增。此过程用于雪崩光电二极管中，当入射光通量非常低时，可以检测单个光子。HgCdTe是雪崩光电二极管的近乎理想的材料，但是，要在室温附近达到最高性能，就需要仔细设计器件结构，以在室温附近达到最高性能。N ⁺ -ν-pP ⁺光电二极管满足分离的吸收区和倍增区的要求。本文介绍了旨在研究HgCdTe N ⁺ -ν-pP ⁺中的碰撞电离机理的研究结果。光电二极管针对230 K下的8μm截止波长进行了优化。结果表明，由于碰撞电离，ν区域的参数极大地影响了电场的分布和发电速率。另外，ν-区域具有减少空间电荷区域中不期望的隧穿的作用。为此目的，必须使该区域中的掺杂保持尽可能低，并且相对于吸收区域扩大能隙。