HgCdTe表面/界面特性对器件性能具有重要的影响, 表面 /界面的状态主要依赖于表面处理和钝化工艺。采用 Br2/CH3OH腐蚀液对液相外延( LPE)生长的中波 HgCdTe薄膜进行表面处理后, 使用 CdTe/ZnS复合钝化技术进行表面钝化, 制备了相应的 MIS器件并进行器件 C-V测试。结果表明, HgCdTe/钝化层界面固定电荷极性为正, 面密度为 2.1×1011 cm-2, 最低快界面态密度为 1.43×1011 cm-2·eV-1, 在 10 V栅压极值下慢界面态密度为 4.75×1011 cm-2, 较低的快界面态密度体现出了 CdTe/ZnS复合钝化技术的优越性。

The HgCdTe surface/interface property plays an important role in HgCdTe based photodiodes, and strongly depends on surface treatment and surface passivation. The LPE HgCdTe surface is etched with bromine in methanol (Br2/CH3OH), followed by sputtering of the CdTe/ZnS composite film as the surface passivation for HgCdTe. MIS devices with ZnS/CdTe double passivation layers are fabricated and characterized. The results show that the polarity of fixed interface charge is positive and interface charge density is 2.1×1011 -2, the minimum magnitude of interface state is 1.43×1011cm-2·eV-1, and the slow interface density is 4.7cm5×1011 cm-2 under the gate bias extreme of 10 V. The relatively low density of interface state indicates that CdTe/ZnS composite passivation technique is advantaged.