Metalorganic vapour-phase epitaxy of AlGaN/GaN heterostructures on chlorine plasma etched GaN templates without buried conductive layer

Abstract

In this work we present approach that allows regrowth of AlGaN/GaN heterostructures on plasma etched GaN templates without occurrence of buried conductive layer. Discussion about the influence of RIE (reactive ion etching) process on the properties of GaN surface is followed by presentation of experimental work results focused on reconstruction of GaN template surface after etching in chlorine plasma in order to growth AlGaN/GaN heterostructure without parasitic channel. Analysis of GaN surface treatment after RIE process using 10% aqueus HF solution and low temperature GaN (LT-GaN) nucleation layer is carried out, including SEM (scanning electron microscopy) imaging and SIMS (secondary ion mass spectroscopy) profiling. The AlGaN/GaN heterostructures with the thickness as low as 250 nm deposited on plasma etched GaN templates with sheet resistance under 600 Ω/□ and good uniformity were fabricated using this approach. Presented method can be used in fabrication of current aperture vertical electron transistor (CAVET) structures with low leakage currents.