کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5361117 | 1388269 | 2008 | 8 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Oxidation of Ni(Pt)Si by molecular vs. atomic oxygen
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
شیمی
شیمی تئوریک و عملی
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چکیده انگلیسی
X-ray photoelectron spectroscopy (XPS) has been used to characterize the oxidation of a clean Ni(Pt)Si surface under two distinct conditions: exposure to a mixed flux of atomic and molecular oxygen (OÂ +Â O2; PO+O2Â =Â 5Â ÃÂ 10â6Â Torr) and pure molecular oxygen (O2; PO2Â =Â 10â5Â Torr) at ambient temperatures. Formation of the clean, stoichiometric (nickel monosilicide) phase under vacuum conditions results in the formation of a surface layer enriched in PtSi. Oxidation of this surface in the presence of atomic oxygen initially results in formation of a silicon oxide overlayer. At higher exposures, kinetically limited oxidation of Pt results in Pt silicate formation. No passivation of oxygen uptake of the sample is observed for total OÂ +Â O2 exposure <8Â ÃÂ 104Â L, at which point the average oxide/silicate overlayer thickness is 23 (3)Â Ã
(uncertainty in the last digit in parentheses). In contrast, exposure of the clean Ni(Pt)Si surface to molecular oxygen only (maximum exposure: 5Â ÃÂ 105Â L) results in slow growth of a silicon oxide overlayer, without silicate formation, and eventual passivation at a total average oxide thickness of 8(1)Â Ã
, compared to a oxide average thickness of 17(2)Â Ã
(no silicate formation) for the as-received sample (i.e., exposed to ambient.) The aggressive silicon oxidation by atomic oxygen, results in Ni-rich silicide formation in the substrate and the kinetically limited oxidation of the Pt.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Applied Surface Science - Volume 254, Issue 22, 15 September 2008, Pages 7486-7493
Journal: Applied Surface Science - Volume 254, Issue 22, 15 September 2008, Pages 7486-7493
نویسندگان
Sudha Manandhar, Brian Copp, J.A. Kelber,