Influence of high Al fraction on reactive ion etching of AlGaN/GaN heterostructures

In this study, the results of reactive ion etching (RIE) process of diversified Al content AlxGa1–xN/AlN/GaN/sapphire heterostructures were presented. The Al fractions of 22, 25, 31 and 36% were examined. An impact of Al content in the heterostructures on the etch rates and surface morphology was investigated. The influence of used Cl2/BCl3/Ar gas mixture with varying of BCl3 flow on the etch rate of Al0.2Ga0.8N/GaN/sapphire, surface morphology and angle of mesa slope, was discussed.