Observations of the Electrical Behaviour of Silicon Carbide Contacts

Abstract

The electrical behaviour of individual silicon carbide contacts has been examined using probes and high resistance electrometer circuits to measure the potential drop across a contact. Voltage-current curves were obtained and the well known departures from Ohm's law at the contact were confirmed. Attempts were made to fit these experimental results and other data to the theoretical expressions for tunnelling through an insulating film, a hypothesis which does not appear to fit the facts very satisfactorily. Observations were made of the effect of heating the material to high temperatures in vacuo, of the properties of a newly formed surface and of the capacitance across the barrier layer. These indicate that the "barrier" has complicated properties which are not consistent with a simple tunnelling model. An alternative model is suggested.