Interface Properties Study on SiC MOS with High-K Hafnium Silicate Gate Dielectric

High k dielectrics, such as Al2O3, has attracted increasing research attention for its use as the gate dielectric of 4H-SiC MOS capacitors. Since the dielectric constant of Al2O3 is not high enough, many other high-k dielectrics are actively explored. In this letter, a report of the interface properties of 4H-SiC MOS capacitors with Hafnium silicate (HfSiOx) dielectric is presented. The HfSiOx dielectric was deposited by thermal atomic layer deposition. A systematic study of I-V and multi-frequency C-V characteristics were carried out and the results showed HfSiOx gate dielectric could effectively increase dielectric constant. A thin layer of SiO2 in between SiC and high k dielectric can further improve interface properties. These results indicate that HfSiOx could be a promising candidate as suitable gate dielectric material for future 4H-SiC MOS capacitors and MOSFETs.