Role of Etching in Aqueous Oxidation of Hydrogen-Terminated Si(100)

• Published in: Journal of physical chemistry. C Vol. 113; no. 23; pp. 10206 - 10214
• Main Authors: Kulkarni, Margaret, Green, Sara K, Shea, Caitlyn, Queeney, K. T
• Format: Journal Article
• Language: English
• Published: American Chemical Society 11.06.2009
• Subjects: C: Surfaces, Interfaces, Catalysis
• ISSN: 1932-7447; 1932-7455
• DOI: 10.1021/jp8114989

Surface infrared spectroscopy is used to examine the initial phases of oxidation of hydrogen-terminated Si(100) in ultrapure water containing dissolved oxygen. Analysis of both Si−O and Si−H vibrational modes suggests that oxide growth occurs in patches and reveals that much of the surface remains unoxidized after 5 h of immersion in O2(aq). Isotopic labeling experiments are used to demonstrate that the same type of surface etching that takes place in O2-free water occurs in the presence of O2(aq). Evidence for surface homogenization during the earliest stages of this etching process suggests that etching might play a critical role in smooth oxide growth, a conclusion supported by the near absence of detectable surface oxidation when etching is virtually eliminated by lowering the solution pH.