Stabilization study of resistive thin films for ac resistors application

This paper presents results on the development of metallic ultra thin films on cylindrical alumina substrate, which are the basis of coaxial ac resistors. Ni₈₀Cr₂₀ and Ni₇₅Cr₂₀Al_2.5Cu_2.5 materials alloy have been used for synthesizing the resistive layers by magnetron sputtering technique. Resistance values as high as 100 k Omega and 200 k Omega have been obtained for both materials respectively over the short substrate length of 45 mm. The characteristics of the layers as homogeneity, thickness, resistances values and stability have been determined and discussed according to the deposit conditions. Specific heat treatments are developed to improve load-life stability of the films.