Initial reaction of hexachlorodisilane on amorphous silica surface for atomic layer deposition using density functional theory

The initial reaction of hexachlorodisilane (Si2Cl6, HCDS) on amorphous silica (SiO2) surface for atomic layer deposition was investigated using density functional theory. Two representative reaction sites on the amorphous SiO2 surface for HCDS reaction, a surface hydroxyl and a two-membered ring, were considered. The reaction energy barrier for HCDS on both sites was higher than its adsorption energy, indicating that it would desorb from the surface rather than react with the surface. At high temperature range, some HCDSs can have kinetic energy high enough to overcome the reaction energy barrier. The HCDS reaction on top of the reacted HCDS was investigated to confirm its self-limiting characteristics.