Spontaneous decomposition of dimethyl gold hexafluoroacetylacetonate on ion bombarded surfaces

Abstract

Aluminum and gold coated quartz crystal oscillators were bombarded by 7 keV Ga+and then exposed to fairly low pressures (~1 mTorr) of dimethyl gold hexafluoroacetylacetonate [denoted Me2Au(hfac)] at room temperature for several hours. While unirradiated crystals exhibit a mass increase corresponding to approximately one monolayer of Me2Au(hfac), irradiated crystals accumulate significantly more mass. Typically, the accumulated mass on the irradiated surfaces corresponds to a film of gold several hundred angstroms thick. Thus, simple condensation of the organometallic molecules cannot explain the large mass increase. Rather it suggests that spontaneous decomposition of the Me2Au(hfac) is occurring on the irradiated surface. X-ray photoelectron spectroscopy indicates that the deposited mass is essentially pure gold. Rutherford backscattering spectroscopy indicates that as many as 20 Au atoms are deposited for each implanted Ga atom. Surfaces irradiated with Au ions show much less mass accumulation, but some growth still occurs. These results indicate that two processes contribute to film growth during ion induced deposition: ion decomposition plus the spontaneous decomposition described here. © 1990, American Vacuum Society. All rights reserved.