Thermal oxidation of hafnium silicide films on silicon

Hafnium silicide films on silicon substrates were oxidized in dry oxygen or in oxygen bubbled through boiling water in the temperature range 400–1000 °C. The progress of the oxidation was followed by measuring the conductivity of the specimen and by Auger analysis. Hafnium silicide films oxidized rapidly even at temperatures below 700 °C; for example, at 700 °C a∼1400-Å silicide film was completely oxidized in 20 min. This oxidation behavior is distinctly different from that of most other silicides on silicon which tend to grow SiO2 instead of the oxidized silicide. The oxidized silicide film inhibited further oxidation of the silicon substrate in dry oxygen but not in steam.