HgCdTe长波光电二极管列阵的等离子体修饰

HgCdTe long-wavelength photodiode arrays modified with high-density hydrogen plasma

报道了HgCdTe长波离子注入n+-on-p型光电二极管列阵低能氢等离子体修饰的研究成果.基于采用分子束外延(MBE)技术生长的HgCdTe/CdTe薄膜材料,通过注入窗口的光刻与选择性腐蚀、注入阻挡层的生长、形成光电二极管的B+注入、光电二极管列阵的低能氢等离子体修饰、金属化和铟柱列阵的制备等工艺,得到了氢等离子体修饰的n+-on-p型HgCdTe长波光电二极管列阵.从温度为78 K的电流与电压(I-V)和动态阻抗与电压(R-V)特性曲线中,发现经过低能氢等离子体修饰的HgCdTe红外长波光电二极管列阵动态阻抗极大值比未经过修饰处理的提高了1～2倍,并在反向偏压大于动态阻抗极大值所处的偏压时动态阻抗得到更为明显的提升.这表明低能氢等离子体修饰可以抑制HgCdTe光电二极管列阵暗电流中的带带直接隧穿电流Ibbt和缺陷辅助隧穿电流Itat,从而能提高长波红外焦平面探测器工作的动态范围和探测性能的均匀性.

The results of high-density hydrogen plasma modification for HgCdTe long-wavelength n＋-on-p photodiode arrays were presented in this paper.n＋-on-p HgCdTe long-wavelength photodiode arrays with photodiode modified by hydrogen plasma immediately after B＋-implantation were fabricated from a Hg1-xCdxTe/CdTe film grown by MBE.The maximum values of the dynamic resistance of the photodiodes in the arrays treated by hydrogen plasma were increased by one to two times compared with those of diodes without modification.The dynamic resistances of the diodes at larger reverse biases away from the maximum point of dynamic resistances were increased more significantly.Thus,it is obvious that hydrogen plasma modification was beneficial to the uniformity of operation dynamic range and detection performance of HgCdTe long-wavelength photodiode arrays because it can suppress the band-to-band tunneling currents and the trap-assisted tunneling currents in the diode.