Regular Article

Potentiostatic controlled nucleation and growth modes of electrodeposited cobalt thin films on n-Si(1 1 1)

¹ Université de Haute Alsace (UHA), Institut de Science des Matériaux de Mulhouse (IS2M), UMR 7361 du CNRS, 3b rue Alfred Werner, 68092 Mulhouse, France
² Université d’Oran 1 Ahmed Benbella, Laboratoire de Physique des Couches Minces et Matériauxpour l’Electronique (LPC2ME), BP 1524, El M’Naouer, 31000 Oran, Algeria

^a e-mail: jean-luc.bubendorff@uha.fr

Received: 22 February 2016
Revised: 6 July 2016
Accepted: 7 July 2016
Published online: 2 August 2016

Abstract

The nucleation and growth of Co electrodeposits on n-Si(1 1 1) substrate have been investigated as a function of the applied potential in a large potential range using electrochemical techniques (voltammetry and chrono-amperometry) and surface imaging by atomic force microscopy (AFM). The surface preparation of the sample is crucial and we achieve a controlled n-Si(1 1 1) surface with mono-atomic steps and flat terraces. Using Scharifker-Hills models for fitting the current-time transients, we show that a transition from an instantaneous nucleation process to a progressive one occurs when the overpotential increases. A good agreement between the nucleation and growth parameters extracted from the models and the AFM data’s is observed. The growth is of the Volmer-Weber type with a roughness and a spatial extension in the substrate plane of the deposited islands that increase with thickness.