Change search
ReferencesLink to record
Permanent link

Direct link
Effects of O-2 dissociation on a porous platinum coating in the thermal oxidation of GaAs
KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
Show others and affiliations
2006 (English)In: Journal of the Electrochemical Society, ISSN 0013-4651, Vol. 153, no 2, G182-G186 p.Article in journal (Refereed) Published
Abstract [en]

A 20-30-nm-thick porous Pt layer has been sputter-coated on a portion of a GaAs sample and subsequently the sample was oxidized at 500 degrees C in O-16(2) followed by O-18-enriched O-2. The oxide formed was characterized by Auger electron spectroscopy, secondary ion mass spectrometry, and X-ray photoelectron spectroscopy, all with a lateral resolution of about 100 mu m. Away from the Pt area, a mm-ranged gradually decreasing degree of As oxidation was observed in the outermost oxide layer. In the Pt area, Ga was preferentially oxidized at the oxide/substrate interface producing a five to seven times thicker oxide than in an area without the influence of Pt. A strongly enhanced dissociation rate of O-2 on Pt particles and a subsequent O spillover to adjacent oxide explain the experimental observations. The mm-ranged spillover is believed to take place via fast lateral surface diffusion and results in the observed variation of oxidized As at the gas/oxide interface. In the Pt area, a high concentration gradient of dissociated oxygen across the oxide layer supplies a high flux of dissociated oxygen to the GaAs substrate where Ga is preferentially oxidized. The results clearly demonstrate that both a surface reaction and solid-state diffusion influence the oxidation rate. A localized high effective oxygen (O) activity that spills over to a nearby oxide area is believed to be a general phenomenon that is operating in oxides where a dissociating element such as Pt is present at O-2/oxide interfaces.

Place, publisher, year, edition, pages
2006. Vol. 153, no 2, G182-G186 p.
Keyword [en]
URN: urn:nbn:se:kth:diva-15370DOI: 10.1149/1.2150156ISI: 000234543400069ScopusID: 2-s2.0-30644472233OAI: diva2:333411
QC 20100525Available from: 2010-08-05 Created: 2010-08-05Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full textScopus

Search in DiVA

By author/editor
Hultquist, Gunnar
By organisation
Corrosion Science
In the same journal
Journal of the Electrochemical Society

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Altmetric score

Total: 47 hits
ReferencesLink to record
Permanent link

Direct link