Proximity Effects of Beryllium-Doped GaN Buffer Layers on the Electronic Properties of Epitaxial AlGaN/GaN Heterostructures

摘要

AlGaN/GaN/Be:GaN heterostructures have been grown by rf-plasma molecular beam epitaxy on freestanding semi-insulating GaN substrates, employing unintentionally-doped (UID) GaN buffer layers with thicknesses, d(sub UID), varying between 50 nm and 500 nm. We have found that the heterostructures with UID buffers thicker than 200 nm exhibit much improved Hall properties and inter-device isolation current compared to heterostructures with d(sub UID).