Characteristics of cobalt thin films deposited by remote plasma ALD method with dicobalt octacarbonyl

Abstract

Cobalt thin films were deposited by a remote plasma atomic layer deposition (ALD) system with a metalorganic precursor of dicobalt octacarbonyl (Co-2(CO)(8)). To investigate the reaction kinetics and the characteristics of the Co films, we carried out experiments, varying parameters such as precursor flow rate and injection time, reactant gas flow rate, plasma power, and substrate temperature. The deposition rate of Co films was similar to 1.2 angstrom/cycle in the ALD window of 75-110 degrees C. The extent of impurity content such as oxygen and carbon was highly affected by plasma power. Two Co films deposited with a plasma power of 50 and 300 W showed different compositional variations. The carbon content of the samples was about similar to 22% and similar to 15%, and oxygen content was about similar to 15% and similar to 2%, for deposition with plasma powers of 50 and 300 W, respectively. The incorporation of impurities was caused by the incomplete decomposition of Co-CO and suppressed Co reaction on Si substrate, retarding silicide formation.