Effects of Dimethylglyoxime and Cyclohexane Dioxime on the Electrochemical Nucleation and Growth of Cobalt

Abstract

© The Author(s) 2018. Published by ECS. Electrodeposition of cobalt on blanket Si with extremely thin cobalt seed was studied in the presence of two additives, dimethylglyoxime (DMG) and cyclohexane dioxime (CHD). Cyclic voltammetry (CV), potentiostatic current transients and galvanostatic nucleation studies were conducted to understand the effects of DMG and CHD on cobalt nucleation process. A typical cross-over in the cathodic sweep was observed in CV studies, consistent with a 3D cobalt nucleation and growth. An interesting "two-peak" phenomenon was observed in the potentiostatic studies with median concentrations of DMG and CHD. A two-step reduction reaction mechanism was proposed. The first peak was identified as the reduction reaction of Co2+ chelate, and the second peak was related to that of free Co2+. This mechanism was further verified with the absence of the second current peak in a solution without free Co2+.