Surface processes leading to carbon contamination of photochemically deposited copper films

Abstract

Copper films exhibiting periodic microstructure have been grown by photolytic decomposition of bis-(1, 1, 1, 5, 5, 5-hexafluoropentanedionate) copper (II) [Cu(hfac)2] and its ethanolate using ultraviolet light, The composition of the films has been analyzed by Auger spectroscopy as a function of cell temperature, precursor, mode of illumination (pulsed or continuous), and light intensity at nearly constant wavelength. The results show that the concentration of the principal contaminant of the films, carbon, is a function of cw light intensity. Addition of ethanol in the form of Cu(hfac)2(ethanol) also has a profound effect on carbon incorporation. Although the elements O and F are a large component of the gas phase copper complex, they are essentially absent from the films under all conditions. These data, when combined with high-resolution analysis of the periodic structures on the films, provide information on surface photochemical and thermal processes likely to be important during film growth. They also allow a general comparison to be made between homogeneous and heterogeneous decomposition of Cu(hfac)2. © 1986, American Vacuum Society. All right reserved.