Oblique angle deposition of columnar niobium films for capacitor application

Abstract

Niobium films with isolated columnar morphology have been prepared by oblique angle magnetron sputtering for capacitor application. Anodizing of the deposited niobium to form dielectric niobium oxide reduces the surface roughness, since the gaps between the neighboring columns are filled with the oxide due to large Pilling-Bedworth ratio for Nb/Nb20s. To increase the gaps between neighboring columns, the infl uences of the angle of niobium flux to substrate and substrate surface roughness on the columnar morphology of the deposited films have been investigated using scanning electron microscopy and the electrochemical measurements. The deposition on the textured rough substrate surface and at higher angle of the niobium flux from normal to the substrate surface fabricates the niobium films with higher surface roughness,©2008 The Japan Institute of Metals.