Atomic layer deposition of tantalum oxide thin films for their use as diffusion barriers in microelectronic devices

Atomic Layer Deposition (ALD) was used for the deposition of tantalum oxide thin films in order to be integrated in microelectronic devices as barrier to copper diffusion. The influence of deposition temperature, number of cycles and precursor pulse time on the film growth was discussed. The conformity of thinnest deposited films was shown. Copper diffusion through ALD Ta2O5 thin films, 20 nm in thickness, was investigated, for three temperatures from 600 to 800 °C, using X-ray Photoelectron Spectroscopy. The failure of such films was detected after a thermal treatment at 700 °C.