Photochemistry of bistriphenyl phosphine nickel dicarbonyl on silicon surfaces: the lithographic deposition of nickel and nickel-iron, nickel-chromium and iron-chromium containing films

Abstract

The photolysis of Ni(CO)₂(PPh₃)₂ as surface films on silicon surfaces has been investigated. The photolysis of the title complex leads to the loss of ligand from the coordination sphere and the formation of nickel. The ligands are largely lost to the gas phase although impurity originating from the triphenylphosphine ligand remains within the film. The controlled construction of films formed from a mixture of Ni(CO)₂(PPh₃)₂ and Cr(CO)₅PPh₃ could be accomplished by spin coating from a solution containing both precursors. Photolysis of films composed of a mixture of Ni(CO)₂(PPh₃)₂ and Cr(CO)₅PPh₃ resulted in the formation of a nickel-chromium film. In a similar fashion films constructed from of Ni(CO)₂(PPh₃)₂ and Fe(CO)₄PPh₃ could be photolysed to generate films of nickel-iron and films composed of Cr(CO)₅PPh₃ and Fe(CO)₄PPh₃ could be photolysed to generate films of chromium-iron. Both of these films contained impurities associated with remnant triphenylphosphine and oxidation of the surface. This process was shown to be compatible with standard lithography techniques by the lithography of 2 μm lines of triphenylphosphine contaminated nickel on a silicon surface.