IEEE Workshop on Wide Bandgap Power Devices and Applications in Asia (WiPDA Asia 2018)

238 / 2017-11-28 16:29:10

A novel Nitrogen Passivation method for improving the SiO2/SiC interface properties

4H-SiC,SiO2/4H-SiC,nitridation,interface traps

Plenary track > Gate dielectrics and surface passivation

A novel technique for improving SiO2/4H-SiC interface properties by over-oxidation the nanoscale heavily nitrogen-doped 4H-SiC epitaxial layer is proposed in this paper. The potential of such method for device application was demonstrated by fabricating and testing Al/SiO2/4H-SiC metal–oxide–semiconductor (MOS) capacitors. The results indicate that this process could strongly reduce the density of interface traps (Dit) without degrading the oxide insulating properties. The Dit extracted using C-V measurements show the lower Dit of about 6×10^11 cm-2•eV-1 at the energy of 0.3 eV below the conduction band, which is comparable with that of conventional NO-annealed process. Finally, secondary ion mass spectroscopy (SIMS) and x-ray photoelectron spectroscopy (XPS) results show that nitrogen atoms, initially introduced by the nanoscale heavily nitrogen-doped epi-layer, have been successfully incorporated at the interface of SiO2/4H-SiC. These results show that the proposed technique is an alternative nitridation technique and can be used to improve the interface properties of the SiO2/4H-SiC.