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/Nb 2 O 5 . To increase the gaps between neighboring columns, the influences 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.

Amorphous niobium oxide thin films

“…Recent papers describe the preparation by thermal evaporation [32], anodization [26,28,30], sputtering [19,29,[33][34][35][36][37][38][39][40][41], sol-gel processes [42][43][44][45], pulsed laser ablation [1,46], spray deposition [22,47], atomic layer deposition [23] and chemical vapor deposition [48].…”

Fully in-situ InAs nanowire Josephson junctions by selective-area growth and shadow evaporation

“…The effective angles created with the two facets on either side are steep with a smaller deposition angles, resulting in column-like growth. 27 Closer inspection of the InAs-Nb interface reveals a ∼1 nm uniform amorphous layer on all three facets (marked by the red dashed lines). Figure 2c shows an EDX line scan across the interface at the position indicated by the yellow arrow in Figure 2b.…”

Co-sputtered amorphous Nb–Ta, Nb–Zr and Ta–Zr coatings for corrosion protection of cyclotron targets for [18F] production

“…This phenomenon can be explained by a tendency of niobium-rich coatings to grow in a columnar microstructure with prolonged grain boundaries through the film, as pure niobium is famous about [71][72][73]. High affinity of niobium to oxygen promotes adsorption of oxygen and forming of niobium oxide in the grain boundaries [74] when sputtering is performed not in ultra-high vacuum, without preliminary degasing of all the system by plasma bombardment [75] and even exposure of pure sputtered niobium films to atmosphere was proven to induce oxidation along the grain boundaries [76].…”