Laser photochemical deposition of gold from trialkylphosphine alkylgold(I) complexes

The deposition of gold bearing tracks, by the argon ion laser photolysis at 257 nm of R'Au^I-PR₃, R,R' = C₂H₅, CH₃, is reported. Deposits were obtained on optically polished fused quartz and (100) n-type single crystal silicon with a thermally grown oxide layer (3000 Å). Tracks were deposited at a range of scan speeds from 0 to 200 µms^-1 and characterized by scanning electron microscopy (SEM), laser ionization mass analysis (LIMA), and scanning profilometry. Electrical resistivities as low as 4.51 µO cm, within a factor of 3 of the value for bulk gold (2.44 µO cm), were measured for tracks deposited at 40 mW and a scanning speed of 7.5 µm s^-1. However, the electrical conductivity of the deposits is highly sensitive to the structure of the organogold precursor. Mass spectral data obtained by LIMA indicate that the incorporation of the precursor and/or various photolysis byproducts into the deposit is related to the volatility of the ligand. Contamination is observed in tracks deposited from compounds containing the heavier ligand. Also, the electrical resistivities are correspondingly higher. Although isothermal annealing above 100°C removes fragments containing the ligand, the resulting electrical conductivities are not improved. © 1994 American Chemical Society.