Thickness dependencies of SiO2/BaOx layers on interfacial properties of a layered gate dielectric on 4H-SiC

We investigated the thickness dependencies of SiO2/BaOx layers on the structural and interfacial properties of a layered gate dielectric on 4H-SiC. The deposition of the SiO2 layer on the BaOx layer changed the stoichiometry and distribution of Ba-silicate in the gate dielectric. Moreover, the interface trap density reduced with increasing SiO2 thickness. The crystal structure changed from amorphous to poly-crystalline with increasing BaOx thickness, indicating the existence of a critical thickness for crystallization. These results show that the properties of gate dielectric/SiC interfaces can be modified by varying the SiO2/BaOx layer thickness.