Effect of deposition parameters on properties of films deposited on fibers by hollow cathode magnetron sputtering

Abstract

Thin films of Al and TiN were deposited on SiC monofilaments using a hollow cathode magnetron sputtering system. The deposition rate was 1100 Å/min in the case of Al films deposited at 45.75 W direct current power and 5 mTorr sputtering pressure and 257 Å/min for TiN films deposited at 6 mTorr sputtering pressure, 6% N2, and 48 W applied direct current power. The effects of deposition parameters such as the direct current power, sputtering pressure, and substrate bias on the film microstructure were studied. The substrate temperature varied from 67.7 to 168 °C, which corresponds to a T/Tm value of 0.1 to 0.25. The Al films consisted of a voided columnar structure with domed tops. The width of the grains increased with increase in temperature over a T/Tm range of 0.1–0.22. When the pressure was increased, while keeping the power constant, the size of the columnar grains and voids decreased. The TiN films deposited at 6 mTorr exhibited zone 1 type structure with voids whereas for the films deposited at higher pressures, that is, 10 and 15 mTorr, the same effect of pressure as in the case of Al films was seen. When a bias is applied to the substrate, the voided structure is clearly suppressed. Preliminary studies show that bias sputtered films show better diffusion barrier properties against both Si and Al, after being annealed at 650 °C for 6 h, as compared to the films deposited without bias.