Electron States at Interfaces of Semiconductors and Metals with Insulating Films

Abstract

Evolution of electron energy barriers at interfaces of AIV (Si, Ge), AIVBIV (GexSi1-x, SiC), and AIIIBV (GaAs, InxGa1-xAs, InP, GaSb) semiconductors with wide-gap oxide insulators is overviewed. Over a wide spectrum of studied materials no significant interface dipole contribution to the barrier height is found. Instead, it appears that the energy position of the top of the O2p-derived oxide valence band remains nearly constant, which can be used to evaluate the interface band alignment between oxides and semiconductors as well as between dissimilar oxides materials. By contrast, barriers for electrons at metal/oxide interfaces appear to be strongly affected by the interface processing indicating that near-interface oxide charges in combination with a resulting polarized metal surface may provide significant dipole contribution to the interface barrier height.