Oxidation-Induced Changes in the ALD-Al2O3/InAs(100) Interface and Control of the Changes for Device Processing

Marjukka Tuominen, Jaakko Mäkelä, Muhammad Yasir, Johnny Dahl, Sari Granroth, Juha Pekka Lehtiö, Roberto Félix, Pekka Laukkanen, Mikhail Kuzmin, Mikko Laitinen, Marko P.J. Punkkinen, Hannu Pekka Hedman, Risto Punkkinen, Ville Polojärvi, Jari Lyytikäinen, Antti Tukiainen, Mircea Guina, Kalevi Kokko

    Research output: Contribution to journalArticleScientificpeer-review

    2 Citations (Scopus)
    35 Downloads (Pure)


    InAs crystals are emerging materials for various devices like radio frequency transistors and infrared sensors. Control of oxidation-induced changes is essential for decreasing amounts of the harmful InAs surface (or interface) defects because it is hard to avoid the energetically favored oxidation of InAs surface parts in device processing. We have characterized atomic-layer-deposition (ALD) grown Al2O3/InAs interfaces, preoxidized differently, with synchrotron hard X-ray photoelectron spectroscopy (HAXPES), low-energy electron diffraction, scanning tunneling microscopy, and time-of-flight elastic recoil detection analysis. The chemical environment and core-level shifts are clarified for well-embedded InAs interfaces (12 nm Al2O3) to avoid, in particular, effects of a significant potential change at the vacuum-solid interface. High-resolution As 3d spectra reveal that the Al2O3/InAs interface, which was sputter-cleaned before ALD, includes +1.0 eV shift, whereas As 3d of the preoxidized (3 × 1)-O interface exhibits a shift of -0.51 eV. The measurements also indicate that an As2O3 type structure is not crucial in controlling defect densities. Regarding In 4d measurements, the sputtered InAs interface includes only a +0.29 eV shift, while the In 4d shift around -0.3 eV is found to be inherent for the crystalline oxidized interfaces. Thus, the negative shifts, which have been usually associated with dangling bonds, are not necessarily an indication of such point defects as previously expected. In contrast, the negative shifts can arise from bonding with O atoms. Therefore, specific care should be directed in determining the bulk-component positions in photoelectron studies. Finally, we present an approach to transfer the InAs oxidation results to a device process of high electron mobility transistors (HEMT) using an As-rich III-V surface and In deposition. The approach is found to decrease a gate leakage current of HEMT without losing the gate controllability.

    Original languageEnglish
    Pages (from-to)44932-44940
    Number of pages9
    JournalACS Applied Materials and Interfaces
    Issue number51
    Publication statusPublished - 26 Dec 2018
    Publication typeA1 Journal article-refereed


    • atomic layer deposition
    • III-V semiconductor
    • InAs
    • oxidation
    • photoelectron
    • synchrotron

    Publication forum classification

    • Publication forum level 2

    ASJC Scopus subject areas

    • Materials Science(all)

    Fingerprint Dive into the research topics of 'Oxidation-Induced Changes in the ALD-Al<sub>2</sub>O<sub>3</sub>/InAs(100) Interface and Control of the Changes for Device Processing'. Together they form a unique fingerprint.

    Cite this