Observations on the phase transformation and its effect on the resistivity of WSi2 films prepared by low-pressure chemical vapor deposition

Abstract

WSi₂ films prepared by low‐pressure chemical vapor deposition were analyzed by backscattering, x‐ray diffraction, and transmission electron microscopy (TEM). The backscattering results indicate that the composition of as‐deposited WSi₂ films does not change during low‐temperature annealing. Crystallographic observations with x‐ray diffraction and TEM on similar samples before and after various heat treatments provide evidence for the low temperature of hexagonal structure of the WSi₂ films. It is transformed into the usual tetragonal structure during low‐temperature annealing. Through x‐ray diffraction examination, the transition temperature is found to be close to 600 °C. This phase transition is correlated to changes of the film resistivity.