HfO2-based insulating stacks on 4H-SiC(0001)

Depositing HfO2 layers on ultrathin thermally grown SiO2 on 4H-SiC(0001) is demonstrated to yield an insulator with good properties. The stack combines the high quality of the ultrathin SiO2/SiC interface and associated high energy barriers for electron and hole injection from SiC with the high dielectric permittivity of HfO2 (approximate to20). The latter allows application of high electric fields to the SiC surface (up to 3 MV/cm), while keeping the strength of the field in the insulator at a moderate level. (C) 2003 American Institute of Physics.