PREPARATION OF W AND MO THIN-FILMS BY RF-DC COUPLED MAGNETRON SPUTTERING

R.f. power and d.c. bias were applied simultaneously to the target in a conventional magnetron sputtering system in order to control the growth kinetics of W and Mo films. The deposition rate of the films is increased with the target d.c. bias because the target current increases with target bias. It is shown that lowering the target bias V(T) down to -100 V results in a significant decrease in the W resistivity to close to the bulk value, while the Mo resistivity is insensitive to V(T). Also, the Ar content in the W film is reduced to below the detection limit of electron probe microanalysis (EPMA, less than 0.01 wt.%) for V(T) = -100 V. An increase in the substrate temperature to 450-degrees-C results in a smooth decrease in the resistivities of W and Mo whose values are close to those of the bulk materials.