Structural and optical properties of silver thin films deposited by RF magnetron sputtering

In this work, we investigate the optical and the structural properties of A g films by means of spectrophotometric techniques and X-ray diffraction met hods in the low- and high-angle regimes. The coatings were grown by radio f requency magnetron sputtering on (100)-oriented silicon substrates. Several sets of samples were produced by varying the sputtering pressure (0.15-0.9 Pa) and changing the sputtering power supply in the range of 25-100 W. In particular, the dependence of the coating optical features, surface roughne ss, texture and residual stress on the parameter beta, proportional to the momentum transferred to the growing film from the energetic particles bomba rding it, was pointed out. The results indicate that the Ag films are polyc rystalline with a moderate [111] texture and compressive in-plane stress wa s measured for all the investigated samples. The behavior of the stress wit h the momentum parameter can be summarized as follows: (i) the compressive stress increases in the range 0 < beta < 300 V(2)s /Angstrom; (ii) at beta similar to 400 V(2)s/Angstrom it shows a very pronounced maximum; (iii) in the range 400 < beta < 800 V(2)s/Angstrom it decreases until reaching a sat uration value for beta > 1000 V(2)s/Angstrom. (C) 2001 Elsevier Science B.V All rights reserved.