Significant Improvement of SiO2/4H-SiC Interface Properties by Electron Cyclotron Resonance Nitrogen Plasma Irradiation

Abstract

The effect of the insertion of a SiN film on the SiO2/4H-SiC interface properties was studied. The SiN interlayer was grown using electron cyclotron resonance (ECR) nitrogen plasma irradiation prior to the SiO2 deposition. It was found that the insertion of a SiN interlayer led to a significant decrease in interface-state and fixed-charge densities in a SiO2/4H-SiC gate stack. This insertion also induced elimination of the near-interface traps in the oxide. It was clarified from X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry analyses that Si dangling bonds were terminated by nitrogen, and the SiN interlayer effectively suppressed the formation of carbon generated by the thermal reaction between SiC and O atoms.