Synthesis of highly conductive cobalt thin films by LCVD at atmospheric pressure

Abstract

We have deposited very low resistant Co films on SiO₂-coated Si substrates using UV pulsed laser pyrolytic decomposition of Co₂(CO)₈ with 355 nm laser radiation at atmospheric pressure. Facile decomposition of the precursors and the use of Ar curtain enable the deposition of relatively pure Co (with O less than 7% and negligible C) at the power of 1.11–3.33 W, and of pure Co at 6.67 W. The resistivity decreases from 58 to 19 µΩ-cm as the power increases from 2.22 to 3.33 W, showing inverse-linear dependence on grain size. In addition, further increase of the power to 6.67 W decreases the resistivity to 9 µΩ-cm, due to both the growth of large grains with negligible contaminants, and the adverse effect of surface roughness. The effects of oxygen contaminants on the resistivity can be minimal, because of its presence in the form of oxide. These low resistant fine metal lines deposited by a direct-writing laser chemical vapor deposition technique at atmospheric pressure have been reported for the first time.