The variation of temperature-dependent carrier concentration and mobility in AlGaN/AlN/GaN heterostructure with SiN passivation

Abstract

The effects of surface passivation effect on electron mobility and crystal structure in Al0.3Ga0.7N/AlN/GaN heterostructures are investigated by classical Hall effect measurements and an X-ray diffraction method. Al0.3Ga0.7N/AlN/GaN heterostructures with different doping and layer structures were grown by molecular beam epitaxy with or without growing an in situ SiN passivation layer. The classical Hall effect measurements were carried out as a function of temperature in the range between T=1.82K and 270K at a fixed magnetic field in dark conditions. The effect of doping of the barrier layer and replacing an AlN inter-layer between the AlGaN barrier and the GaN layer, where the two-dimensional electron gas is populated, on mobility and sheet carrier concentration were also determined.