Molecular‐beam epitaxy of AlN on off‐oriented SiC and demonstration of MISFET using AlN/SiC interface

Abstract

Molecular-beam epitaxy (MBE) of AlN on 4H-SiC epilayers with the off-cut angle of 8° was performed using elemental Al and rf-plasma excited active nitrogen (N*) toward the goal of MISFETs using the AlN/4H-SiC hetero-interface. AlN films grown at 600 °C had a very flat surface with monolayer-height steps. Control of atomic arrangement at the AlN/4H-SiC interface was attempted by pre-irradiation of active nitrogen to achieve MIS structures with excellent electrical characteristics. The electronic properties of AlN/4H-SiC interface were characterized by C-V measurements of Al/AlN/n-type 4H-SiC MIS capacitors. The interface states at the AlN/4H-SiC interface were revealed to be strongly influenced by pre-irradiation of active nitrogen. Planar-type n-channel AlN/4H-SiC MISFETs were fabricated using a gate-stacked structure with SiO2. Owing to the novel device structure as well as an optimized AlN growth condition, we could first demonstrate the good transistor operation of MISFETs using the AlN/4H-SiC interface. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)