Surface reverse etching analysis of (Al)GaN-capped AlGaNGaN high electron mobility transistors

Abstract

AlGaN/GaN-based high electron mobility transistor heterojunction with different thickness (Al)GaN cap layers were grown by metalorganic vapor phase epitaxy (MOVPE). The thickness of the cap layers was examined by X-ray photoelectron spectroscopy. It could be seen that the actual thickness of the GaN cap layer was about 1 nm thinner than the theoretical thickness, and however the results of the Al0.04Ga0.96N cap layer was basically the same. The surface quality was tested by atomic force microscopy and the strain properties of the cap layer were characterized by photoluminescence.