ABSTRACT
Abstract-Pulsed laser irradiation before or after film deposition strongly enhances the bonding between metallic films and ceramic substrates. Low-energy ion bombardment of the substrate prior to film deposition also promotes strong bonding with ceramic substrates. Irradiation by laser and ions produces in many instances metastable structures. In consistency with previous results, it is reported that laser irradiation of sapphire substrates prior to film deposition strongly enhances the copper film-sapphire bonding. The effect of the oxygen content in the irradiation atmosphere on metal/oxide adhesion bonding is analyzed with particular reference to alumina and sapphire substrates. The presence of oxygen during irradiation promotes strong bonding because it produces an intermediate compound. However, an oxygen-containing atmosphere is not a requisite for the formation of a strong bond between a metallic film and an oxide substrate. Irradiation in a reducing atmosphere in the case of laser, or at low pressure during ion bombardment, also promotes a very strong bond. The oxygendepleted surfaces produced by these treatments have metastable structures with high reactivity that also form intermediate compounds. In all cases studied here, the presence of an intermediate or an interfacial compound appears to be the main factor responsible for the adhesion enhancement.
