Modulating Schottky barrier of metal/p-type 4H-SiC by thin insulator TiO2 layer intercalation

We have investigated the barrier modulation of an electrically homogeneous Ni/p-type 4H-SiC contact by intercalation of a thin insulator TiO2 layer. It is found that the TiO2 layer can provide an extra barrier increase, resulting into the barrier height at the interface exceeding the Schottky–Mott limit. However, the barrier is inhomogeneous and Gaussianly distributed over the contact area. The barrier inhomogeneity may be due to an increase in interface states density caused by the oxide induced traps. The increase in barrier height is believed to originate from an electrostatic potential increase across the dipole layer related to the induced positive polarization charges on the p-type 4H-SiC surface.