碲镉汞光伏型探测器的变面积氢化研究

STUDY ON VARIABLE-AREA HYDROGENATION OF HgCdTe PHOTOVOLTAIC DETECTORS

利用氢等离子体对碲镉汞光伏型探测器进行了变面积氢化处理研究,发现随着氢化面积的变大,器件的电流-电压(I-V)特性得到明显改善,表现在器件的暗电流变小,零偏电阻R0变大,同时器件的电流噪声也随着氢化面积的扩大而逐渐降低.通过对比实验结果和数值拟合结果,认为氢化工艺对器件性能的改善机制与氢化区域有关,当氢化区域限于N型区时,氢化的效果主要表现在降低注入损伤导致的少子复合中心从而提高少子寿命;当氢化区域扩大到P型区时,氢化的效果主要表现在使表面耗尽区中的陷阱中心减少,主要通过降低间接隧道电流来改善器件性能,这说明了实验中注入成结的光伏器件为N+P结.

Variable-area hydrogenation of HgCdTe photovohaic （PV） detectors was studied. It was found that the currentvoltage（I-V） characteristic was obviously improved after hydrogenation, wherein dark current was gradually decreased as the hydrogenation area enlarged, and the zero-biased resistance was increased, meanwhile the current noise was reduced. By the comparison of experimental results and numerical fitting results, it was found that .the improvement of I- V curveswas related to hydrogenation zone. When the hydrogenation process was focused on the N-type zone, hydrogenation effect was mainly due to the reduction of minority carrier recombination centers caused by implantation process, which could increase the minority carrier lifetime. When the hydrogenation was enlarged to P-type zone, the improvement was primarily the resuh of the oppression of trap density in the surface depletion region, which led to the decrease of trap-assisted tunneling current. So it was concluded that the junctions of PV detectors formed by ion implantation were N^＋ P type.