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XeF[sub 2] etching of Si(111): The geometric structure of the reaction layer

Journal Article · · Physical Review, B: Condensed Matter; (United States)
; ; ; ; ;  [1]
  1. Department of Physics, University of California, Riverside, California 92521 (United States) Materials Sciences Division, Lawrence Berkeley Laboratory, Berkeley, California 94720 (United States)

Si(111)-7[times]7 is exposed to XeF[sub 2] in ultrahigh vacuum and examined with soft-x-ray photoelectron spectroscopy (SXPS) and photon-stimulated desorption (PSD). The exposures encompass the entire range from chemisorption to steady-state etching. By taking into account the different surface sensitivities of SXPS and PSD, the microscopic structure of the surface fluorosilyl reaction layer is obtained as a function of exposure, and the reaction process is modeled. It is found that the reaction-layer structure passes through four distinct exposure regimes. Steric hindrance between the F atoms of neighboring fluorosilyl groups and defects in the substrate are responsible for the evolution of the reaction-layer structure. When steady-state etching is reached, the reaction layer evolves to a tree'' structure of fluorosilyl chains terminated at the surface by SiF[sub 3] groups.

DOE Contract Number:
AC02-76CH00016
OSTI ID:
6397386
Journal Information:
Physical Review, B: Condensed Matter; (United States), Journal Name: Physical Review, B: Condensed Matter; (United States) Vol. 47:23; ISSN PRBMDO; ISSN 0163-1829
Country of Publication:
United States
Language:
English