Annealing effects on zirconium nitride films

ZrN films were deposited by dc reactive magnetron sputtering on silicon substrates under optimized nitrogen partial pressure of $6 x 10^{-5}$ mbar. Structural, electrical and optical properties were systematically investigated. Films deposited at room temperature exhibited Schottky structure without any silicide interfacial layer. These films have electrical resistivity of $4.23 x 10^{-3}$ $\Omega$ cm, which were crystalline in nature, with cubic (1 1 1) orientation. Refractive index and extinction coefficient were found to be 1.95 and 0.43, respectively at a wavelength of 350 nm. Samples were annealed for 1 h in air at two temperatures, 350 and 550 $^oC.$ Scanning electron microscopy (SEM) and energy dispersive analysis of X-rays (EDAX) showed alloy penetration pits. Extent of penetration was greater in the films, which were annealed at higher temperature $(550 ^oC).$ Variation in refractive index was observed in the range of 1.95–1.80 at 350 nm, for the annealed films, with increase in grain size from 7.25 to 11.10 nm. Poly-crystalline nature has been observed with (1 1 1) and (2 0 1) orientations. Resistivity is found to increase from $4.23 X 10^{-3}$ to $6.21 X 10^{-3} \Omega cm.$