Oxidation and protection in copper and copper alloy thin films

Abstract

The oxidation kinetics of copperthin films have been studied at temperatures below 200 °C in air. The protection of copper from oxidation can be achieved by alloyingcopperfilm with Ti, Pd, Cr, or Al. The influence of the composition and microstructure to the oxidation rate has been studied. The compounds Cu3Ti, Cu3Pd, and CuAl2 are stable in the oxidation ambient. The formation of Cr‐oxide, which is a passive oxide, explains the inhibition of oxidation on Cu‐Cr films. Compared with the crystalline phase, the amorphousCu65Ti35alloyfilm is more oxidation resistant. A TiN layer with oxygen incorporated is more effective in preventing copperoxidation than a TiN layer without oxygen incorporated. A passivating Si3N4 layer on copperthin films can prevent copperoxidation effectively at 350 °C in oxygen ambient.