Reduction of buffer leakage current in AlGaN/GaN high-electron-mobility-transistor structure on Si substrate by reducing the dislocation density in AlN buffer layer

We investigated preferable way of decrease of vertical leakage current in GaN-based high-electron-mobility-transistor structure on Si(111) substrate. It is found that the leakage current is much improved as the dislocation density in thin A1N buffer layer decreases. It has been successfully obtained the leakage current less than 10-4 A/cm2 at 200 V although the total epitaxial layer thickness is about only 1 mum.