By utilizing preexposure of helium plasma, a method of depositing a blanket tungsten layer directly on SiO2 has been developed. When SiO2 films are exposed to a helium plasma, oxygen atoms are knocked on by active species in the plasma and the surface becomes covered with reduced silicon. It is assumed that this silicon reacts with WF6 to form tungsten nuclei, and that tungsten layers grow through the reaction of H2 and WF6 at these nuclei. The deposited tungsten layer is stable with a low resistivity in the form of the α-W crystal and shows strong adhesion to the SiO2 film due to the anchoring effect of tungsten.
ASJC Scopus subject areas
- Physics and Astronomy(all)