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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. [ABSTRACT FROM AUTHOR]

This paper reviews the feasibility of the state-of-the-art electrical techniques adopted from Si technology for characterization of SiC MOS devices. The inability of these conventional characterization techniques to correctly evaluate the trap capture cross section and field-effect mobility in SiC MOS devices are investigated and explained. As near-interface traps (NITs) are an important cause of field-effect mobility degradation in SiC MOS devices, which is different from the impact of interface traps in Si devices, these characterization techniques are unable to produce meaningful results. Therefore, special care is required when measuring these NITs in SiC MOS devices. Due to the quantum confinement effect, the NITs located above the conduction band edge are able to capture and release channel electrons from the conduction band via tunnelling. Recent characterization techniques, specifically designed for SiC MOS devices, measure the NITs above the bottom of conduction band and consider the quantum confinement effect to find the energy position of the NITs. These recent characterization techniques are presented in the later part of the paper. [ABSTRACT FROM AUTHOR]