Electrodeposition of copper onto modified monocrystalline silicon surfaces

MARIA B. QUIROGA ARGAÑARAZ; JOAQUÍN KLUG; G. RIVEROS PATRONI; GABRIELA I. LACCONI

New London

Conferencia; Gordon Research Conferences - Electrodeposition; 2010

Gordon Research Conferences

Surface modification of silicon with highly robust Si-C linked organic monolayers iscurrently an area of intensive research not only because of its technological applications forpassivating or bio-functionalizing semiconductor devices but also for the study of chemicaland electronic processes at the semiconductor surface [1]. The preparation of hybridmolecular-semiconductor devices or chemical biosensors requires a detailed understandingof the silicon/organic layer interface.It is very well-known that the anodic oxidation of silicon surfaces is a preparationmethod for very thin and reproducible oxides to be used in ultralarge-scale integrateddevices [2]. On the other hand, various synthetic strategies have been developed over thepast few years to form alkyl-terminated and functionalized monolayers on silicon. Theseinclude photochemical and thermally induced hydrosilylation, free-radical initiation and Lewisacid catalyzed reactions [3].The purpose of this communication is to study the electrochemical oxidation of thehydrogenated-Si(111) surfaces in order to obtain suitable platforms for studying theproperties of biological membranes. The synthesis and characterization of compact alkylmonolayers covalently attached to n-Si(111) surfaces is also performed. The aim of theinvestigation is completed by copper electrodeposition onto the functionalized surfaces [4].The electrochemical behaviour of Si(111)-H surfaces is performed by the anodicoxide growth obtained under different experimental conditions (potential-time program,solution pHs, etc.). Functionalized surfaces (Si-R) are obtained by the formal hydrosilylationreaction between 1-octadecene and Si-H substrates, which is initiated by heating thesamples at temperatures over 140 ºC, different time periods.The electrochemical characterization of the organic functionalized silicon surfaceswas performed by cyclic voltammetry, principally related to the inhibition of the silicon oxideformation. Direct correlations between the electrical properties of the film, hydrophobicity ofthe layer and passivation of the surface with the experimental conditions of the synthesis areestablished. On the other side, copper was electrodeposited onto the functionalized siliconsurface by the application of potential pulses. The results show that the nuclei formationoccurs at the monolayers defects. The kinetic of nucleation and growth of the coppercrystals was established by the analysis of the current transients at different potential values.Structural characterization of the oxidized, derivatized surfaces and the copper depositedcrystallites was performed by ex-situ NC-AFM.References1.- G. Oskam, J. G. Long, A. Natarajan and P. C. Searson, J. Phys. D: Appl. Phys. 31 (1998)1927 – 1949.2.- F. Bensliman, A. Fukuda, N. Mizuta, M. Matsumura, J. Electrochem. Soc. 150 (2003)G527 - G531.3.- Bruno Fabre, Fanny Auquier, Philippe Allongue J. Electroanal. Chem. 629 (2009) 63– 68.4.- M. B. Quiroga Argañaraz, Cecilia I. Vázquez and G. I. Lacconi, J. Electroanal. Chem. 639(2010) 95 – 101.