A surface study of wet etched AlGaN epilayers grown by hot-wall MOCVD

Comparative study of NH4OH and HCl etching behaviours on AlGaN surfaces

“…The area surface roughness yields a root mean square (RMS) value of pristine AlGaN layer of 0.56 nm which was almost halved by wet chemical etching yielding the RMS values of 0.25 nm for NH 4 OH treated and 0.21 nm for HCl treated samples. The AFM measurements on HCl treated surfaces yields the least roughness RMS value of 0.21 nm; this is comparable with the previously reported values [25,26]. Indeed such improvement of surface morphology is beneficial to improve the carrier mobility and therefore facilitate the performance enhancement of HEMT devices [27].…”