Filament-assisted reactive magnetron sputter deposition of VSiN films

Abstract

Many vapor deposition techniques utilize ion irradiation during growth of transition metal nitride-based films to obtain low porosity and to control nanostructural evolution, phase content, and crystallographic texture. In this study, V1-xSixN films (0.18 ≤ x ≤ 0.30) were deposited by a reactive magnetron sputtering process in which a heated filament was used to enhance growth temperature and ion bombardment. Filament discharge current (0.0 A ≤ ID ≤ 2.6 A) and sputter target powers (PV = 500 W,250 W, PSi = 180 W,90 W) were varied among depositions. With filament-assistance, substrate current densities doubled relative to the current densities achieved without the filament. Atomic force microscopy, scanning electron microscopy, and electrical resistivity measurements indicated that the use of the hot filament reduced the porosity present in the deposited films. X-ray diffraction revealed that all VSiN films contained a single crystalline phase with a crystal structure and lattice spacing similar to NaCl-type VN. Texture coefficient calculations showed that increases in filament discharge current initially enhanced (111) texturing until, at the maximum filament discharge current, a mixed (111)/(200) texture was obtained. Film hardness and elastic modulus were measured using nanoindentation and found to scale with filament discharge current to maximum values of 16 GPa and 218 GPa, respectively. Rockwell indentation tests revealed that film adhesion decreased with increases in filament discharge current and film deposition rate. Telephone cord blisters were observed in films deposited at the highest filament discharge currents confirming that the ion irradiation conditions generated compressive residual stresses.