Full-Wafer, Small-Area Via-Hole Fabrication Process Development for Indium- Bearing III-V Heterostructure Devices

摘要

Three different dry etch chemistries (Cl_2/Ar, BCl_3/Cl_2/Ar, and SiCl_4/Ar) were evaluated for full-wafer, small-area via-hole fabrication in indium-bearing III-V heterostructure devices. The process was developed and demonstrated using InGaP/GaAs/InGaAs inverted metamorphic triple-junction backside contact photovoltaic cells as the baseline heterostructure. Uniform, vertical and smooth etch profiles were obtained through the heterostructures, despite the widely varying material compositions. Optical emission spectroscopy was used to track the process in real time for improved process control. The results obtained by etching small test samples are compared with those from full 4" wafers, and the differences in etch behavior are discussed.