The Schottky limit and a charge neutrality level found on metal/6H-SiC interfaces

Abstract

We report the Schottky limit and a charge neutrality level (CNL) experimentally demonstrated at metal/6H-SiC(0 0 0 1) interfaces. An interface with the Schottky limit was formed by dipping SiC surfaces in boiling pure water before metallization. The total density of interface states, D it, was a drastically small value of 4.6×10 10 states cm −2/eV, indicating the density of the metal induced gap states was less than this value. In contrast, at incompletely passivated interfaces without the boiling water dipping process, a broad continuum of interface states with D it of 2.8×10 13 states cm −2/eV was observed with the CNL located at 0.797 eV from the conduction band minimum. The origin of these interface states was found to be in the disordered interface layers.