Effect of Solvent on the Growth of Co and Co2C Using Pulsed-Spray Evaporation Chemical Vapor Deposition

Abstract

Cobalt and cobalt carbide films were obtained using chemical vapor deposition (CVD) at low pressure in a hydrogen-free atmosphere at temperatures below 300 °C. Although the growth over bare glass was enabled, the use of a 5 nm nickel seed layer improves the morphology and eliminates the incubation time. The pulsed-spray evaporation using alcohol solutions of cobalt acetylacetonate as a liquid feedstock allows the growth of metallic cobalt or cobalt carbide, depending on the choice of the alcohol and of the deposition temperature. The growth of Co2C was obtained, for the first time with CVD, using an ethanol precursor solution at temperatures in the range of 205–230 °C, whereas the deposition of high-quality metallic crystalline cobalt is attained with an n-propanol precursor solution at substrate temperatures above 250 °C. The obtained metallic films reach a near-bulk electrical resistivity for thicknesses above 300 nm.