Electrical characterization of SiC MOS capacitors: A critical review

Abstract

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.