HIGH-FIELD AND HIGH-TEMPERATURE STRESS OF N-SIC MOS CAPACITORS

The development of reliable oxides built on SiC has become a very impo rtant issue with respect to either passivation processes or metal-oxid e-semiconductor (MOS) applications. The aim of this paper is to presen t a detailed investigation of Fowler-Nordheim electron injections in n -type silicon carbide (SiC) MOS capacitors. A systematic variation in the temperature and in the average oxide held E-OX applied during the stress allowed us to evidence both a positive charge and electron trap ping. The positive charge build-up is shown to emerge above a threshol d field close to 7 MV cm(-1). It decreases with temperature, and can b e dissociated into two different exponential time processes. The overa ll results agree with mechanisms based on impact ionization in the oxi de, leading to pair creation and subsequent hole trapping. (C) 1997 El sevier Science S.A.