Differential Variable Base Charge Pumping (Δ-CP) for SiO2/SiC Interface Characterization

We propose an electrical evaluation technique named differential charge pumping (Delta-CP) to extract information on the interface states (D-it) at the SiC/SiO2 interface. This technique allows to obtain information on (1) the physical location of the D-it; (2) the energetic spread of the Dit in the bandgap; (3) if the D-it are donor or acceptor type. First results indicate contributions from both the "S/D" region and the channel regions to the overall CP signal. Surprisingly a substantial contribution of the "S/D" regions of the transistors to the overall CP signal is observed. In the channel region, both donors and acceptor type states are identified, the majority being acceptor type.