The Oxidation of Silicides on Silicon

Abstract

Under proper care the oxidation of silicide films formed over silicon substrates results in the formation of metal-free layers of silicon oxide. The silicide layers themselves appear to be unaffected by the oxidation process. The overall kinetic and thermodynamic conditions which make this possible are reviewed. The growth of the oxide is always faster over the silicides than over (100) silicon, but semiconducting silicides with large band gaps oxidize almost as slowly as silicon, whereas silicides with a strongly metallic character oxidize rapidly. Other factors such as whether the formation of the oxide layers occurs from the direct diffusion of silicon atoms or through the decomposition (followed by the reconstitution) of the silicide are considered. Some attention is also paid to such problems as that of the formation and behavior of point defects generated by the silicidation and oxidation processes.