INFLUENCE OF HYDROGEN PRESSURE ON THE PROPERTIES OF CVD TUNGSTEN SILICIDE FILMS

In this paper, the properties of low pressure chemically vapor deposit ed tungsten silicide films processed from tungsten chlorides and silan e are studied as a function of hydrogen initial partial pressure. By m eans of thermodynamic calculations, we have defined a priori the opera ting conditions leading to each silicide deposition. The corresponding films are grown in a cold-wall reactor and characterized by x-ray dif fraction and scanning electron microscopy studies. Good agreement betw een theoretical and experimental results is obtained. The increase of initial hydrogen partial pressure has two possible consequences: a mod ification of the film composition for high WCl4 partial pressure and a modification of the film growth rate for lower WCl4 partial pressure.