Energy-Localized Near-Interface Traps Active in the Strong-Accumulation Region of 4H-SiC MOS Capacitors

Abstract

Near-interface traps (NITs) with energy levels aligned to the conduction band and spatially located close to the SiO2/SiC interface are responsible for significant degradation of the channel-carrier mobility in 4H-SiC MOSFETs. In this paper, we investigate fast trapping and detrapping of the conduction-band electrons by NITs with energy levels localized between 0.13 and 0.23 eV above the bottom of the conduction band. The trapping and detrapping times were estimated to be in the range between the resolution limit of tens of nanoseconds and $1~\mu \text{s}$ by measuring the current through n-type MOS capacitors in response to a ramped voltage in the accumulation region.