Non-uniform distribution of induced strain in a gate-recessed AlGaN/GaN structure evaluated by micro-PL measurements

Micro-photoluminescence (µ-PL) studies were performed on AlGaN/GaN heterostructure field effect transistors (HFETs) with different gate-recessing depths. It was found that µ-PL is the method of choice for detecting dry etching damage and simultaneously recording strain and stress in the HFET GaN layer. Lateral sub-µm resolved mapping shows that the strain in the GaN layer after recessing is partially relaxed and non-uniform. (paper)