SiC MOSFETs with thermally oxidized Ta2Si stacked on SiO2 as high-k gate insulator

In this paper, we compare the electrical characteristics of MOS capacitors and lateral MOSFETs with oxidized Ta2Si (O-Ta2Si) as a high-k dielectric on silicon carbide or stacked on thermally grown SiO2 on SiC. MOS capacitors are used to determine the dielectric and interfacial properties of these insulators. We demonstrate that stacked SiO2/O-Ta2Si is an attractive solution for passivation of innovative SiC devices. Ta2Si deposition and oxidation is totally compatible with standard SiC MOSFET fabrication materials and processing. We demonstrate correct transistor operation for stacked O-Ta2Si on thin thermally grown SiO2 oxides. However the channel mobility of such high-k MOSFETs must be improved investigating the interface properties further.