NANO STRUCTURE CONTROL OF HETERO-INTERFACE FOR METALLIC MULTILAYERS BY USING NEW FABRICATION TECHNIQUE WITH THE SUBSTRATE EXCITED BY SURFACE ACOUSTIC WAVES

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The aims of this study is to fabricate the matallic multilayrs of which situations at the interface between the different two metals were optimized in atomic scale, and to develop the sensing devices for magnetic field with high sensitivity, by means of applying the new fabricating technology for thin film with using the substrate excited by surface acoustic waves (SAW). Prior to fabricating multilayrs, the monitoring method for initial growth stage of matallic thin films, which is indispensable for fabricating multilayrs, were developed and worth results were obtained as summarized below. The detailed relations between the strong dumping of SAW and the microstructures of metallic thin films at the initial growth stage were investigated. The mass thickness, at which the SAW amplitude reaches minimum were found to correspond to the critical thickness, at which the film structure changes from island-like to continuous. From the investigation for the influence of metal seed layrs on initial film growth by referring above relations, it was found that islands of the seed layr capture the adatoms diffused over the substrate surface, becom growth centers for the subsequent film deposition, and help to make smooth surface of ultra thin metallic films. The structural changes of ultra thin metallic firms with low melting point like as Ag and Cu were also observed, when depositions were stopped at the initial growth stages. Standing on these results, Co/Cu multilayrs were fabricated on the substrate excited by SAW under various SAW amplitude, and estimated those sensing properties. In the multilayr which was fabricated under small SAW amplitude, the maximum magnetoresistance ratio was observed, and the optimized interfacial structure was realized.