Density functional study of initial HfCl4 adsorption and decomposition reactions on silicon surfaces with SiON interfacial layer

The initial adsorption and decomposition of HfCl4 on silicon surfaces with different types of SiON interfacial layers are investigated using density functional theory. We find that the reactions of HfCl4 on both the hydroxylated and nitrided silicon surfaces proceed through similar reaction pathways. By comparison of the reaction energies of HfCl4 with the hydroxyl and amino surface sites, we find that it is both kinetically and thermodynamically favorable for the reactions of HfCl4 on hydroxyl site of silicon substrates. Comparing with the adjacent bridging oxygen, we also find that the neighboring hydroxyl can facilitate the adsorption of HfCl4 on the amido surface site. Also, it is more kinetically and thermodynamically favorable for the reaction of HfCl4 with bridging NH site than that with NH2 site.