Selective Electrodeposition of micropatterns on predefined surface defects on p-Si(100)

The present work investigates selective metal electrodeposition reactions triggered by intentionally created surface defects on p-type Si(100) surfaces. Defined defects were written into the Si surface by focused ion beam (FIB) Si2+ implantation. Subsequently, Au was electrochemically deposited on the samples from a 1 M KCN+0.01 M KAu(CN)(2) solution. The work demonstrates that selective Au deposition can be achieved; i.e., that electrochemical conditions can be established where Au deposition occurs exclusively on the FIB-treated regions. The key principle is that breakdown of the current blocking situation (established at the p-type semiconductor/electrolyte junction under cathodic bias) is facilitated at surface defects. Thus this local current flow can be exploited to achieve localized Au deposition. The lateral resolution of the process is in the 100 nm range. The main parameters influencing the nucleation and growth of Au deposits and their morphology, as well as the selectivity and resolution of the process, are the implant dose and the electrochemical conditions during Au deposition. The work shows that the implant dose directly affects the density of nucleation sites for the electrodeposition process. Coverage of an implanted area is obtained, if sufficient nucleation sires are activated in the deposition process either using high implant doses or high deposition potentials. Since the concept presented in this work potentially can be applied for many electrodeposition reactions, it may open new perspectives for patterning of semiconductor surfaces with a large palette of materials in the submicrometer scale. (C) 2001 The Electrochemical Society. All rights reserved.