INTERFACIAL REACTIONS OF W THIN-FILM ON SINGLE-CRYSTAL (001)BETA-SIC

Interfacial reactions between a W thin film and a single-crystal (001) beta-SiC substrate on rapid thermal annealing a from 600 degrees C to 1100 degrees C for 60 a were investigated by backscattering,o spectrometry, X-ray diffraction, secondary ion mass spectrometry and cross-sectional transmission electron microscopy. Backscattering spectrometry shows that W reacts with SiC at 950 degrees C. The product phases identified by X-ray diffraction are W5Si3 and W2C. At 1100 degrees C no more unreacted W is detected. Current-voltage measurements show that ohmic contacts are already obtained on as-deposited W. Contact resistivity measured using the circular transmission line model is about 10(-3) Ohm cm(2). Thermodynamic studies of the solid phase stability in the ternary W-Si-C system help us to understand the chemical stability of W thin film.