Oblique angle deposition of columnar niobium films for capacitor application

Niobium films with isolated columnar morphology have been prepared by oblique angle magnetron sputtering for capacitor application. Anodizing of the deposited mobium to form dielectric mobium 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/Nb2O5. To increase the gaps between neighboring columns, the influences of the angle of mobium 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 mobium flux from normal to the substrate surface fabricates the mobium films with higher surface roughness.