DEPOSITION OF CARBON-FILMS BY BIAS MAGNETRON SPUTTERING IN NEON AND ARGON

The results from a comparative study of the magnetron sputtering deposition process of carbon films carried out in neon and argon are reported. First the conditions for ion-assisted thin film growth in the two gases are compared. These conditions are characterized by (i) the deposition rate, (ii) the ratio Cion of the noble gas ion to sputtered atom arrival rates and (iii) the average energy of the ions extracted at a given bias voltage. It was found that at a given discharge power and gas pressure the ion and deposition fluxes in neon are approximately twice those in argon. Consequently the ratio Cion has nearly the same range of variation, while the deposition rate in neon is much higher; this may be important for practical application. To estimate the effect of the deposition conditions on the film properties, the resistivity of the films was measured as a function of substrate bias, gas pressure and discharge power. The general behavior of the film resistivity was found to be similar in both gases. The main differences observed can be understood in terms of differences in the plasma parameters and in the conditions for transport of sputtered material in the two gases. © 1990.