Influence of vacuum annealing on interface properties of SiC (0001) MOS structures

Abstract

We investigated the influence of vacuum annealing on the interface properties of silicon carbide (SiC) metal-oxide-semiconductor (MOS) structures. For as-oxidized and nitric oxide (NO)-annealed samples, the interface state density (D it) near the conduction band edge (E C) of SiC did not increase by subsequent vacuum annealing. For phosphoryl chloride (POCl3)-annealed samples, in contrast, D it at E C-0.2 eV increased from 1.3 × 1010 to 2.2 × 1012 cm-2 eV-1 by vacuum annealing, and the channel mobility of MOS field effect transistors (MOSFETs) decreased from 109 to 44 cm2 V-1 s-1. The mechanism of the observed increase in D it was discussed based on the results of the secondary ion mass spectrometry measurement.