Properties of tungsten silicide thin films obtained by magnetron sputtering of composite cast targets

Summary form only given. The standard technique of deposition of thin films, having the silicide composition and structure, involves magnetron sputtering of a pure metal film onto the surface of a silicon substrate and then high-temperature annealing. Deposition of thin films by magnetron sputtering of compacted silicide powder targets is of limited use because of the high content of gaseous and light metallic impurities stipulated by standard powder metallurgy processes. Thin silicide films deposited by sputtering such targets have high electrical resistivity and comparatively low reproducibility. A more advantageous procedure is deposition of silicide films by magnetron sputtering cast silicide targets of the necessary chemical composition. However, the casting of silicide targets for commercial magnetron sputtering is a well-known metallurgical problem because solidified tungsten silicides are very brittle. It seems that the optimal solution of this problem, which enables one to produce cast silicide sputtering targets, is mosaic targets consisting of copper bases and small cast silicide ingots attached to the base by soldering or another procedure. In this study we present our experimental results on the thin tungsten silicide films deposited by magnetron sputtering of mosaic cast tungsten disilicide targets. The cast tungsten disilicide ingots have been produced from 5N-purity silicon and high-purity tungsten.