Oxidation of the GaAs semiconductor at the Al2O3/GaAs junction

Marjukka Tuominen, Muhammad Yasir, Jouko Lång, Johnny Dahl, Mikhail Kuzmin, Jaakko Mäkelä, Marko Punkkinen, Pekka Laukkanen, Kalevi Kokko, Karina Schulte, Risto Punkkinen, Ville-Markus Korpijärvi, Ville Polojärvi, Mircea Guina

    Research output: Contribution to journalArticleScientificpeer-review

    9 Citations (Scopus)


    Atomic-scale understanding and processing of the oxidation of III-V compound-semiconductor surfaces are essential for developing materials for various devices (e.g., transistors, solar cells, and light emitting diodes). The oxidation-induced defect-rich phases at the interfaces of oxide/III-V junctions significantly affect the electrical performance of devices. In this study, a method to control the GaAs oxidation and interfacial defect density at the prototypical Al2O3/GaAs junction grown via atomic layer deposition (ALD) is demonstrated. Namely, pre-oxidation of GaAs(100) with an In-induced c(8 × 2) surface reconstruction, leading to a crystalline c(4 × 2)-O interface oxide before ALD of Al2O3, decreases band-gap defect density at the Al2O3/GaAs interface. Concomitantly, X-ray photoelectron spectroscopy (XPS) from these Al2O3/GaAs interfaces shows that the high oxidation state of Ga (Ga2O3 type) decreases, and the corresponding In2O3 type phase forms when employing the c(4 × 2)-O interface layer. Detailed synchrotron-radiation XPS of the counterpart c(4 × 2)-O oxide of InAs(100) has been utilized to elucidate the atomic structure of the useful c(4 × 2)-O interface layer and its oxidation process. The spectral analysis reveals that three different oxygen sites, five oxidation-induced group-III atomic sites with core-level shifts between -0.2 eV and +1.0 eV, and hardly any oxygen-induced changes at the As sites form during the oxidation. These results, discussed within the current atomic model of the c(4 × 2)-O interface, provide insight into the atomic structures of oxide/III-V interfaces and a way to control the semiconductor oxidation.

    Original languageEnglish
    Pages (from-to)7060-7066
    Number of pages7
    JournalPhysical Chemistry Chemical Physics
    Issue number10
    Publication statusPublished - 14 Mar 2015
    Publication typeA1 Journal article-refereed

    Publication forum classification

    • Publication forum level 1

    ASJC Scopus subject areas

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


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