Enhancement of deposition rates in the reactive sputtering of silicon exposed to an argon-oxygen plasma

Abstract

Silicon oxide films were prepared by the reactive radio frequency (rf) sputtering in an Ar-O2 plasma. The deposition rates were measured as a function of oxygen mole fraction in the sputtering gas and sputtering power. It was found that the deposition rate was abruptly enhanced at a critical oxygen mole fraction in an Ar-O2 plasma. This enhancement was attributed to chemical sputtering of the Si target by argon ion bombardment in the oxygen atmosphere. Thus, the reactive sputtering of a Si target in an argon-oxygen plasma was found to consist of three modes, namely, (i) physical sputtering of oxidized target surface, (ii) chemical sputtering, i.e., release of species having very low energy, and (iii) physical sputtering of metallic target surface.