LOW-TEMPERATURE RADIO-FREQUENCY SPUTTER-DEPOSITION OF TIN THIN-FILMS USING OPTICAL-EMISSION SPECTROSCOPY AS PROCESS MONITOR

TiN films were deposited onto various substrates including InP by rf s puttering in an N-2/Ar ambient at room temperature. The rf power, the ratio of gas flows, and the total pressure were systematically varied. To optimize the deposition conditions, the plasma excitation processe s were examined by optical emission spectroscopy using a calibrated cr ystal thickness monitor to determine the corresponding deposition rate s. At pressures below 15X10(-3) mbar, the deposition rate is linearly proportional to the intensity of the optical emission at 364.2 nm, I(T i), associated with excited Ti. Although I(Ti) increases with the tota l pressure, at a given rf power, the resulting deposition rate decreas es at pressures above 20x10(-3) mbar due to greater gas-phase scatteri ng. The [N]/[Ti] ratio in the deposited films, as determined by Ruther ford backscattering and Auger electron spectroscopy, is found to be li nearly correlated with the ratio of the optical emission intensities o f excited N-2(+) (391.4 nm) and Ti at 364.2 nm, I(N-2(+))/I(Ti).