FORMATION OF STACKED INSULATION FILMS ON ROUGH METAL-SURFACES

Insulation films with a stacked structure were formed on metal surfaces via a combination of the sol-gel and sputtering processes. Thin films of Ta2O5 prepared by the sol-gel process were effective in planarization of rough metal surfaces. Sputtered SiO2 films were deposited on the sol-gel Ta2O5 films thus formed, and the insulation properties were evaluated by resistance measurements. It was found that the insulation properties of stacked films of the sputtered SiO2 and sol-gel Ta2O5 films were much better than those of only sputtered or sol-gel films. It can be concluded from this result that sol-gel films were effective in planarization of concave regions, and that sputtered films were mainly formed on convex or summit areas of rough metal surfaces.