INTERFACE AND ELECTRICAL-PROPERTIES OF PLASMA-DEPOSITED TUNGSTEN AND TUNGSTEN NITRIDE SCHOTTKY CONTACTS TO GAAS

Abstract

Comparison of plasma enhanced chemical vapor deposited tungsten and tungsten nitride (W0.67N0.33) Schottky contacts to GaAs are carried out at the rapid thermal annealing temperature of 500-1000-degrees-C for 30 s without arsenic overpressure and capping layer. The Rutherford backscattering measurement, cross-sectional transmission electron microscopy, and secondary ion mass spectroscopy indicate that no metallurgical interactions take place between W0.67N0.33 and GaAs. Hall measurements and I-V characteristiCS of W0.67N0.33 Schottky contacts exhibit higher temperature stability than W contacts to GaAs, which is ascribed to the role of interstitial nitrogen atoms blocking the outdiffusion of Ga and As.