ELECTRICAL-PROPERTIES OF THERMAL OXIDE GROWN ON N-TYPE 6H-SILICON CARBIDE

Measurement of current conduction in the metal/thermal oxide/n-type 6H-silicon carbide is reported. The thermal oxides were grown on nitrogen-doped n-type 6H-silicon carbide at 1275-degrees-C in a dry oxygen ambient. Analysis indicates a Fowler-Nordheim type current conduction mechanism with a barrier height of 2.7 eV between silicon carbide and oxide. Using this value an electron affinity of 3.7-3.8 eV was determined for the Si face of 6H-silicon carbide. The breakdown field strength for the oxides grown on n-type 6H-silicon carbide was 10 MV/cm which is comparable to the breakdown field strength of thermal oxides grown on silicon. Capacitance-voltage measurements indicated that the interface between n-type silicon carbide and the thermally grown oxide has a low (5 X 10(10) cm-2 eV-1) interface trap density (D(it)). The effective charge density in the oxide was estimated to be 1 X 10(11) cm-2. These measurements indicate that the quality of oxides thermally grown on 6H-silicon carbide is comparable to those grown on silicon.