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Mechanistic studies of palladium thin film growth from palladium(II) {beta}-diketonates. 2. Kinetic analysis of the transmetalation reaction of bis(hexafluoroacetylacetonato)palladium(II) on copper surfaces

Journal Article · · Journal of the American Chemical Society
DOI:https://doi.org/10.1021/ja944131+· OSTI ID:282999
; ;  [1]
  1. Univ. of Illinois, Urbana, IL (United States)
The reaction pathways and kinetics for the selective deposition of palladium on copper from the metal-organic precursor Pd(hfac){sub 2} have been established by means of reactive molecular beam-surface scattering where a flux of Pd(hfac){sub 2} (ranging from 10{sup 13} to 10{sup 14} molecules cm{sup -2} s{sup -1}) impinges continuously on the copper surface. The surface selectivity of the deposition process is a consequence of a `redox transmetalation` reaction, which is best described by the stoichiometric equation Pd(hfac){sub 2} + Cu {yields} Pd + Cu(hfac){sub 2}. On polycrystalline copper foils, the production and subsequent desorption of Cu(hfac){sub 2} from the surface occurs with unit efficiency at temperatures between 400 and 600 K. At temperatures above 600K, the yield of Cu(hfac){sub 2} decreases and eventually falls to zero at 800 K as the thermolytic decomposition of the hfac ligands on the surface becomes kinetically competitive. We have devised a steady-state kinetic model of the adsorption of Pd(hfac){sub 2}, desorption of Cu(hfac){sub 2}, and thermolytic decomposition of hfac molecules that quantitatively fits the decrease in Cu(hfac){sub 2} yield seen at higher temperatures. The transmetalation reaction follows an apparent power rate law that is first order in Cu and first order in hfac coverage. The steady-state kinetic model accurately predicts the deposition rate so long as diffusion of the Pd atoms into the Cu bulk is relatively fast. 24 refs., 7 figs.
DOE Contract Number:
FG02-91ER45439
OSTI ID:
282999
Journal Information:
Journal of the American Chemical Society, Journal Name: Journal of the American Chemical Society Journal Issue: 25 Vol. 118; ISSN JACSAT; ISSN 0002-7863
Country of Publication:
United States
Language:
English