Enhancement of SiO2/Si(001) interfacial oxidation induced by thermal strain during rapid thermal oxidation

Shuichi Ogawa, Jiayi Tang, Akitaka Yoshigoe, Shinji Ishidzuka, Yuji Takakuwa

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)

Abstract

Rapid thermal oxidation, in which samples are intensely heated to a preset temperature, is used to grow silicon oxide on Si substrates while avoiding significant diffusion of impurities into the substrate. In previously proposed reaction models for rapid thermal oxidation, the oxidation rate is only determined by the temperature and O2 pressure. Therefore, it is believed that the rate of oxidation at a preset temperature is independent of the initial substrate temperature. In this study, the interfacial oxidation reactions that follow Si(001) surface oxidation were observed using real-time Auger electron spectroscopy. Interfacial oxidation was enhanced when the substrate temperature was increased from temperature T1 to temperature T2 at the end of Si(001) surface oxidation. As a result, strong T1 and T2 dependences of the interfacial oxidation rate were observed. The interfacial oxidation rate at T1 = room temperature was more than 10 times higher than that at T1 = 561 °C, even for the same T2 (682 °C). Additionally, the activation energy of interfacial oxidation was 0.27 eV, and independent of T1. This activation energy corresponds to the "no elementary step" proposed as the rate-limiting reaction in previous studies. These results can be explained using the unified Si oxidation reaction model mediated by point defect generation: high magnitude thermal strain is generated when the difference between T2 and T1 is large, and this strain generates point defects that become reaction sites for interfacial oxidation.

Original languageEnglish
Article number114701
JournalJournal of Chemical Physics
Volume145
Issue number11
DOIs
Publication statusPublished - 2016 Sep 21

ASJC Scopus subject areas

  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry

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