Interface chemistry of WNr4H–SiC structures

The interface chemistry of WNr4H–SiC structures has been studied by means of X-ray photoelectron spectroscopy XPS.. XPS investigations have been performed on as deposited, 8008C and 12008C annealed 4 min.samples. The as deposited and 8008C annealed samples are characterized by chemically inert interfaces. Complete nitrogen out-diffusion from the WN layer, significant carbon diffusion into the contact layer, tungsten carbide and tungsten silicide formation occur during the 12008C annealing process. The 8008C annealed WNr4H–SiC contacts are found to be of a Schottky type with a barrier height of 0.91 eV. The Schottky barrier height and the ideality factor show no significant changes during 100 h storage at 5008C under nitrogen and during operation at increasing temperature up to 3508C in air. q1999 Elsevier Science B.V. All rights reserved.