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Local SiO 2 formation in silicon bombarded with oxygen above the critical angle for beam‐induced oxidation: new evidence from sputtering yield ratios and correlation with data obtained by other techniques
Author(s) -
Wittmaack K.
Publication year - 2000
Publication title -
surface and interface analysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.52
H-Index - 90
eISSN - 1096-9918
pISSN - 0142-2421
DOI - 10.1002/1096-9918(200010)29:10<721::aid-sia916>3.0.co;2-q
Subject(s) - sputtering , yield (engineering) , silicon , analytical chemistry (journal) , atomic physics , neon , chemistry , rutherford backscattering spectrometry , ion , oxygen , atom (system on chip) , x ray photoelectron spectroscopy , projectile , argon , materials science , thin film , nuclear magnetic resonance , physics , nanotechnology , organic chemistry , chromatography , computer science , metallurgy , embedded system
The first direct comparison of the angular dependence of the sputtering yield of silicon under bombardment with oxygen and inert gas ions of similar mass (neon) is reported. The O 2 + /Ne + ratio of the yields, measured at the same energy per projectile atom (5 keV), increases smoothly from 0.33 at 0° to a constant value of 0.89 above ∼65°. This large‐angle ratio agrees with the number expected from the projectile mass dependence of sputtering yield theory. The experimental data were analysed on the basis of the assumption that the measured sputtering yield is the sum of contributions from areas composed of either SiO 2 or (mostly) Si. The SiO 2 fractions thus derived agree quite well with results obtained recently in studies on ion‐induced electron emission. Combining the present results with literature data on the angular dependence of the composition of oxygen‐bombarded silicon measured by x‐ray‐induced photoemission spectroscopy, ion‐induced electron emission and Rutherford backscattering spectrometry, the SiO 2 fractions were found to increase roughly with the square of the O/Si ratio. Data presentation as a function of the atomic fraction of oxygen, on the other hand, gives rise to misleading interpretations. Implications of the results for the interpretation of secondary ion yields and ripple formation are discussed briefly. Copyright © 2000 John Wiley & Sons, Ltd.