AlGaN layers grown on GaN using strain-relief interlayers

Abstract

We report on a study to compare the growth of thick AlGaN layers on GaN with different strain-relief interlayers. A set of ten period AlN/AlGaN superlattices was found to be the most efficient approach for the strain relief. The superlattice interlayer not only decreases the tensile strain but also improves the crystal structural quality. Thus, 2-μm-thick, high quality n+-Al0.2Ga0.8N layers can be grown on GaN epilayers without any cracks.