BOMBARDMENT AND GAS RAREFACTION EFFECTS ON THE PROPERTIES OF SPUTTERED TI THIN-FILMS

The effects of deposition pressure and sputtering power on the properties of Ti films have been investigated. Ti films of two different thickness ranges have been deposited by d.c. magnetron sputtering at nominally 50 degrees C substrate temperature with various deposition pressures and sputtering powers. For films 650 nm thick, the film density shows a drop of 20% and electrical conductivity decreases by a factor of 2 with increasing deposition pressures from 0.07 to 1.33 Pa at a sputtering power of 3 kW. However, at the higher power of 10 kW, the film density and electrical conductivity are relatively unchanged with increasing deposition pressure. For thinner films of 65 nm, no significant effect of pressure on the film density and electrical conductivity is observed at either power level. These results can be explained by the effect of densification of film microstructure due to high energy of incident particles at low pressures. The application of high power sputtering, however, diminishes this effect by the rarefaction of the sputter gas through increased energy and momentum transfer.