The Influence of 1nm AlN Interlayer on Properties of the Al0.3Ga0.7N/AlN/GaN HEMT Structure

The sheet carrier concentrations, conduction band profiles and amount of free carriers in the barriers have been determined by solving coupled Schrodinger and Poisson equation self-consistently for coherently grown Al"0"."3Ga"0"."7N/GaN and Al"0"."3Ga"0"."7N/AlN/GaN structures on thick GaN. The Al"0"."3Ga"0"."7N/GaN heterojunction structures with and without 1nm AlN interlayer have been grown by MOCVD on sapphire substrate, the physical properties for these two structures have been investigated by various instruments such as Hall measurement and X-ray diffraction. By comparison of the theoretical and experimental results, we demonstrate that the sheet carrier concentration and the electrons mobility would be improved by the introduction of an AlN interlayer for Al"0"."3Ga"0"."7N/GaN structure. Mechanisms for the increasing of the sheet carrier concentration and the electrons mobility will be discussed in this paper.