Properties of sequentially sputtered tungsten silicide thin films

Multilayered WSi sub chi films with chi = 0.4 and chi = 2 have been RF sputtered onto GaAs wafers under UHV background conditions. In order to study the structural and morphological properties of as-deposited and annealed films secondary ion mass spectrometry, Raman spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and transmission electron microscopy have been performed. The individual layers of WSi(0.4) films prepared at room temperature are smooth on an atomic scale while those deposited at 300 degree C show a high degree of corrugation. In addition the X-ray diffraction pattern indicates the existence of microcrystalline W which does not change in size after annealing in the case of films prepared at 300 degree C. The silicide formation of the WSi2 films depends on the thickness of the individual with the occurence of an additional phase which is identified as W5Si3.