Chemical vapor deposition of Cu films from copper(I) cyclopentadienyl triethylphophine: Precursor characteristics and interplay between growth parameters and films morphology

Abstract

The rough, even discontinuous morphology of vapor-deposited copper films inhibits their attractive electrical properties. In the present study, we investigate the influence of deposition time, deposition temperature, and the flow rate of the precursors on the morphology of Cu films deposited from metalorganic chemical vapor deposition. We show that it is necessary to purify the copper(I) cyclopentadienyl triethylphophine (CpCuPEt3) precursor in order to improve its stability and volatility. We also determined its saturated vapor pressure law, logPsat (Pa) = 8.614 - 2272/T (K). The Arrhenius plot of the global deposition reaction of Cu films in the presence of hydrogen between 431 and 523 K shows a low apparent activation energy of 10 kJ/mol. Electron probe microanalysis, grazing incidence X-Ray diffraction, and image analysis of the micrographs obtained by top–down surface scanning electron microscopy reveal metallic films composed of Cu islands. Their size and packed density increase and, ultimately, the islands coalesce with increasing precursor flow rate and, to a lesser extent, with increasing deposition temperature.