Fermi-level pinning and passivation on the oxide-covered and bare silicon surfaces and interfaces

The properties of the bare (oxide-free) and oxide-covered silicon have been discussed in details in the literature. Positive charge is usually assumed at the insulator-semiconductor interface, thus depletion or inversion layer develops in the case of p-type, and accumulation in the case of n-type semiconductor. However, the semiconductor (Si) covered by an ultra-thin tunnelable insulator (native SiO2) layer has some peculiarities, i.e. connection between surface charge and the interface charge carrier density. Theoretical considerations and vibrating capacitor experiments show that the surface charge tends to shift the surface nearer to the intrinsic condition in the case of the ultra-thin insulator-covered semiconductor surfaces. (C) 2002 Elsevier Science Ltd. All rights reserved.