【摘要】 在同一Hg1-xCdxTe晶片上(x=0.217)制备了单层ZnS钝化和双层(CdTe+ZnS)钝化的两种器件,对器件烘烤前后的暗电流和1f噪声进行了测试,烘烤前发现,ZnS钝化的器件在反偏较大时具有较大的表面隧道电流,而这种表面漏电流是ZnS钝化器件具有较大1f噪声电流的原因,通过高分辨x射线衍射中的倒易点阵技术(reciprocal spacemapping,RSM)研究了单双层钝化对HgCdTe外延层晶格完整性的影响,发现单层ZnS钝化的HgCdTe外延层产生了大量缺陷,而这些缺陷正是ZnS钝化器件具有较大表面漏电流和1f噪声的原因.经过高温烘烤后,ZnS钝化的器件暗电流和1f噪声增加,而双层钝化器件经过高温烘烤后性能提高.RSM的研究表明,高温烘烤后ZnS钝化的HgCdTe外延层产生大量缺陷,这些缺陷正是单层钝化器件表面漏电流和1f噪声电流增加的原因.更多还原

【Abstract】 The long_wavelength infrared Hg 1- x Cd x Te photovoltaic detectors with x =0 217 passivated by single ZnS layer and dual (CdTe+ZnS) layers were fabricated in the same wafer. The fabricated devices were characterized by measurements of dark currents and 1/ f noise. The diode passivated by dual (CdTe+ZnS) layers showed a higher performance compared to the diode passivated by the single ZnS layer at high reverse bias, and modeling of diode dark current mechanisms indicated that the performance of the diode passivated by single ZnS was strongly affected by tunneling current related to the surface defects, which was responsible for the dark currents and 1/ f noise characteristics. By the analysis of x_ray reciprocal space map (RSM), it was found that the Q y direction broadening of HgCdTe epitaxial layer passivated by ZnS was wider after passivation, which confirmed the existence of defects in the surface of HgCdTe epitaxial layer passivated by ZnS. In order to investigate the effect of surface passivation on the stability of two kinds of diodes, dark currents and 1/ f noise of the diodes were measured after vacuum baking for 10 h at 80℃. The dark current mechanisms indicated that the performance of the diode passivated by single ZnS was strongly affected by the surface defects. By the analysis of RSM, It was found that the Q y direction broadening of HgCdTe epitaxial layer passivated by ZnS was wider after high_temperature baking, which also confirmed the existence of defects in the surface of HgCdTe epitaxial layer passivated by ZnS after baking.更多还原