CONTAMINATIONS AND IMPURITIES IN DC MAGNETRON-SPUTTERED WSIX FILMS ONSIO2 - AN ANALYTICAL STUDY

In this study, dc magnetron sputtered WSi(x) films are characterized w ith RBS, SIMS, and TEM techniques. The films are deposited in a Varian 3180 sputtering system with the commag WSi target 91-1209-05. Contami nations emitting from the shutter and cavity shields in the deposition chamber are reduced with the application of particle getter (PG). RBS analysis shows the films to contain 1.1 at% Ar and 0.11 at% Mo impuri ties along with WSi(x) and SiO2. SIMS mass spectra also reveal the pre sence of Mo in WSi(x) layer. The Si to W ratio (Si/W) and at% Mo incre ase with target use. No significant changes in the Si/W are observed w ith annealing in the temperature regime 700 to 1000-degrees-C The shee t resistivity of the WSi(x) films decreases with increasing RTA temper atures. The TEM and XRD results of as-deposited samples show the films are amorphous and the annealed samples are polycrystalline with tetra gonal WSi2 phase. The annealed samples show the presence of larger gra ins and increased precipitation of silicon within the film. The low sh eet resistance (12.2 OMEGA/.), conductivity, stability, good uniformit y, fine grains, and manageable stress for good adhesion makes WSi(x) a promising gate electrode material for submicron CMOS technologies.