Evolution of protrusions during sputtering from composite Ag–Si targets

In this paper we describe studies on the effects of the sputtering pressure and power on shape and size of microscopic protrusions formed on a target consisting of a small Ag plate placed on a Si wafer. The influence of the target topography change during sputtering on the composition of the sputter‐deposited film was investigated. It was found that the Ag concentration of the deposited films was considerably reduced with the growth of the target surface protrusion on Ag plates. This is considered to be attributable to the prevention of sputtered atoms from escaping from the target by surface protrusions.