Morphology changes of Si(001) surfaces during wet chemical halogenation

This paper reports an experimental study aimed to develop a suitable and reliable procedure to graft organic molecular fragments onto silicon surfaces, leading to a stable organic termination. Grafting of self-assembled organic films on the (0 0 1) surface of Si is performed by SC1/SC2 processing and by a bromination step preceding the nucleophilic reaction with the organic aromatic compound. After each wet processing step the Si(0 0 1) morphology is investigated using atomic force microscopy to correlate the etching chemistry and the substrate morphology. The bromination step is observed to cause a strong increase of surface roughness due to the formation of pyramid-shaped nanostructures. Controlling the surface roughness as induced by chemical processing is suggested as a fundamental goal towards an increase of the organic film coverage and stability. Correcting actions and enabling prevention of surface damage are proposed and discussed. (C) 2003 Elsevier Science B.V. All rights reserved.