Control of selective tungsten chemical vapor deposition by monolayer nitridation of silicon surface

Selective tungsten chemical vapor deposition was carried out on three kinds of substrates: hydrogen-terminated silicon (H-SI), monolayer nitrided silicon (N-Si), and thermally grown silicon oxide. X-ray photoelectron spectroscopy (XPS) confirmed that the H-SI substrates differ from the N-Si substrates only by the monolayer of nitride on their surface. Field-emission scanning electron spectroscopy and XPS showed that tungsten does not deposit on the N-Si substrates but does deposit on the H-SI substrates. Monolayer nitridation therefore has the potential for improving and optimizing the thin-film preparation processes, because it provides a means for altering the surface reactivity while keeping the bulk properties unchanged.