MOVCD生长GaAs/AlGaAs量子阱红外探测器暗电流特性研究

Analysis on Dark Current Characteristic of GaAs/AlGaAs Quantum Well Infrared Photodetectors Grown by MOVCD

摘要:

用金属有机物化学气相沉积法（MOCVD）生长了GaAs/AlGaAs量子阱材料，分别制备了300μｍ×300μｍ台面，峰值波长805μｍ，外电极压焊点面积80μｍ×80μｍ，内电极压焊点面积20μｍ×20μｍ的单元测试样品。用变温液氦制冷机测试系统对两个样品进行50～300Ｋ的变温测试，分析了器件在不同偏压条件下的暗电流特性。发现该量子阱红外探测器的背景限温度为50Ｋ。不同生长次序中GaAs与AlGaAs界面的不对称性，以及掺杂元素的扩散导致了正负偏压下的I/V曲线呈不对成性。探测器电极压焊点面积大小与位置的不同对暗电流有一定的影响。

Abstract:

GaAs/AlGaAs quantum well infrared photodetectors with the peak wavelength of 8.5μm were grown by Metal Chemical Vapor Deposition (MOVCD). Two sample devices were obtained with a large area of 300μm×300μm and the pressure welding area of 80μm×80μm and 20μm×20μm for the outside electrode and the insideelectrode respectively. Refrigerating machine of liquid helium was adopted to make variable-temperature tests from 50K to 300K, and the dark current characteristics were analysed under different bias voltages. Tests results indicate the background limited temperature of the samples is 50K. It is the interfacial asymmetry of GaAs and AlGaAs in different growing order and the doping element diffusion that leads to the asymmetry of the I/V curve under positive and negative bias. The different pressure welding area and position of the electrodes may influence the dark current.