基于MIS电容器的Al_(2)O_(3)与In_(0.74)Al_(0.26)As的界面特性

Interfacial properties between Al_(2)O_(3) and In_(0.74)Al_(0.26) As epitaxial layer on MIS capacitors

采用In_(0.74)Al_(0.26)As/In_(0.74)Ga_(0.26)As/In_(x)Al_(1-x)As异质结构多层半导体作为半导体层,制备了金属-绝缘体-半导体(MIS)电容器。其中,SiN_(x)和SiN_(x)/Al_(2)O_(3)分别作为MIS电容器的绝缘层。高分辨率透射电子显微镜和X射线光电子能谱的测试结果表明,与通过电感耦合等离子体化学气相沉积生长的SiN_(x)相比,通过原子层沉积生长的Al_(2)O_(3)可以有效地抑制Al_(2)O_(3)和In_(0.74)Al_(0.26)As界面的In2O3的含量。根据MIS电容器的电容-电压测量结果,计算得到SiN_(x)/Al_(2)O_(3)/In_(0.74)Al_(0.26)As的快界面态密度比SiN_(x)/In_(0.74)Al_(0.26)As的快界面态密度低一个数量级。因此,采用原子层沉积生长的Al_(2)O_(3)作为钝化膜可以有效地降低Al_(2)O_(3)和In_(0.74)Al_(0.26)As之间的快界面态密度,从而降低In_(0.74)Ga_(0.26)As探测器的暗电流。

Metal-Insulator-Semiconductor(MIS)capacitors were fabricated on In_(0.74)Al_(0.26)As/In_(0.74)Ga_(0.26)As/In_(x)⁃Al1-xAs heterostructure multilayer semiconductor materials.SiN_(x) and SiN_(x)/Al_(2)O_(3) bilayer were applied as insulating layer to prepare MIS capacitors respectively.High-resolution transmission electron microscopy(HRTEM)and X-ray photoelectron spectroscopy(XPS)measurements indicated that,compared with SiN_(x) deposited by inductively coupled plasma chemical vapor deposition(ICPCVD),Al_(2)O_(3) deposited by atomic layer deposition(ALD)can ef⁃fectively suppresses In2O3 at the interface between Al_(2)O_(3) and In_(0.74)Al_(0.26)As.According to the capacitance-voltage(C-V)measurement result of MIS capacitors,the fast interface state density(Dit)of SiN_(x)/Al_(2)O_(3)/In_(0.74)Al_(0.26)As was one order of magnitude lower than that of SiN_(x)/In_(0.74)Al_(0.26)As.Therefore,it can be concluded that Al_(2)O_(3) deposited by ALD as a passivation film can effectively reduce the interface state density between Al_(2)O_(3) and In_(0.74)Al_(0.26)As,thereby reducing the dark current of p-In_(0.74)Al_(0.26)As/i-In_(0.76)Ga_(0.24)As/n-In_(x)Al1-xAs photodiodes.