Growth of niobium oxide films on single-crystal silicon

200-nm-thick niobium films grown on single-crystal silicon wafers by magnetron sputtering have been oxidized by annealing in flowing oxygen. X-ray diffraction examination revealed the metal-like phase Nb 6 O in the as-deposited films. Annealing in flowing oxygen for 1 h led to the formation of tetragonal NbO 2 at 570 K and hexagonal Nb 2 O 5 at temperatures above 770 K. The grain size and surface roughness of the films were evaluated using atomic force microscopy.