Low Gate Leakage Current and Interface State Density of Atomic Layer Deposition Al2O3 SiC MOS Device with NH3 Plasma Treatment

Abstract

We have investigated the impacts of NH3 remote-plasma treatment with various plasma exposure times on the chemical and electrical characteristics of an ALD Al2O3 SiC MOS device. NH3 remote-plasma passivation was carried out, prior to Al2O3 deposition. The atomic force microscopy indicates that remote NH3 plasma treatment reduces surface roughness. Auger Electron Spectroscopy, Secondary Ion Mass Spectrometry depth profile and X-ray Photoelectron Spectroscopy spectra reveal that nitrogen is effectively incorporated at the interface between Al2O3 and SiC by NH3 plasma treatment. Compared to MOS device without NH3 plasma passivation, lower gate leakage current and interface state density (D-it) are attained with NH3 plasma passivation. Further forming gas annealing (FGA) improves interface quality. The best characteristics are obtained by NH3 passivation for 15 min with additional FGA and the D-it value is 4.6x10(11) cm(-2)eV(-1).