Passivation of copper by silicide formation in dilute silane

The formation of copper silicide by reaction of silane with sputtered copper films has been observed at temperatures as low as 300 °C. The growth kinetics have been monitored by both sheet resistance and x-ray diffraction techniques. Cu5Si is the first phase to form followed next by Cu3Si, coincident with the loss of the original copper layer. The silicide layer provides significant oxidation protection for the underlying copper up to 550 °C in air.