Some comments on the determination and interpretation of barrier heights of metal–semiconductor contacts

Abstract

The intrinsic interface-induced gap states are the fundamental theoretical concept which explains the band-structure lineup at all semiconductor interfaces. However, a comparison of experimental results and theoretical predictions requires data of well-characterized interfaces. With respect to the experimental input, two aspects are of importance. First, the evaluation of the measured data has to be performed critically and very carefully and, second, extrinsic and intrinsic effects have to be recognized and then separated. Some examples are given. The interpretation of the experimental data may become misleading if a physical quantity such as the Fermi-level stabilization energy of heavily radiation-damaged semiconductors is considered which derives from the complex semiconductor band-structure as the branch-point of the interface-induced gap states.