Surface Barriers at Semiconductor Contacts

The voltage-current and capacity-current characteristics for current flow across a surface of discontinuity between two semiconductors have been derived. Both the diode and diffusion theories are dealt with, the former being treated in detail for Mott barriers and the latter for Schottky barriers. The results are applied to measurements on silicon carbide point contacts and a grain boundary in germanium respectively. The resistance is shown to be consistent with a barrier which is caused by donor and acceptor surface states. On S 1 C the density of these states is about 10 13 cm -2 and on Ge about 5 × 10 11 cm -2 .