AVS 45th International Symposium
    Surface Science Division Wednesday Sessions
       Session SS1-WeM

Paper SS1-WeM8
Electroless Deposition of Au onto H-Si(111)

Wednesday, November 4, 1998, 10:40 am, Room 308

Session: Physics of Semiconductors
Presenter: R. Srinivasan, Clarkson University
Authors: I. Suni, Clarkson University
R. Srinivasan, Clarkson University
Correspondent: Click to Email
Electroless deposition of Au from aqueous HF onto p-type H-Si(111) has been studied by electrochemical methods, atomic force microscopy (AFM), Rutherford backscattering (RBS), and surface second harmonic generation (SHG). The H-terminated Si(111) surface is prepared by HF etching prior to Au deposition. We have found evidence that Au deposition occurs by a two-step process, where initial deposition of AuCN is rate-limited by diffusion, while subsequent reduction of Au is rate-limited by surface reaction involving a fluoride-containing species. The growth of Au nanoclusters can be monitored by SHG through the development of the surface plasmon resonance, which occurs above a threshold cluster size of about 2 nm. The SH signal goes through a temporal maximum and then declines again due to interdiffusion of Au and Si. Surface kinetics can then be analyzed by manipulating the solution phase equilibria and following the effects on Au reduction by SHG. This analysis reveals that HF, not HF@sub 2@@super -@, is the mechanistically important species and that Au reduction is half-order in HF.