Color of titanium nitride prepared by reactive dc magnetron sputtering

Abstract

The color of titanium nitride films deposited by reactive dc magnetron sputtering has been investigated as a function of elemental composition obtained by Auger analysis. At an average target current density of 44 mA cm−2 the nitrogen flow rate was varied from 0.02 Pa m2 s−1 to 0.06 Pa m2s−1 while argon flow was fixed such that a flow rate of 0.11 Pa m3s−1 resulted in a system pressure of 1.33 Pa. Hence average film growth rates at the substrate plane 4.75 cm away varied from 3000 Å/min to 600 Å/min as the target surface changed from titanium to titanium nitride. The various colors obtained are specified in terms of dominant wavelength, purity, and brightness from results obtained by spectrophotometric measurements. The values are compared with sputtered 18 kt gold. It is found that changes in elemental composition as a result of incorporation of background reactive gases other than nitrogen as the metal sputtering rate and substrate bias is changed, has a profound effect on color and also on other properties like wear and corrosion resistance.