A1 Journal article – refereed
Oxidation of the GaAs semiconductor at the Al2O3/GaAs junction

List of Authors: 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
Publication year: 2015
Journal: Physical Chemistry Chemical Physics
Journal acronym: PHYS CHEM CHEM PHYS
Volume number: 17
Number of pages: 7
ISSN: 1463-9076


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 x 2) surface reconstruction, leading to a crystalline c(4 x 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 x 2)-O interface layer. Detailed synchrotron-radiation XPS of the counterpart c(4 x 2)-O oxide of InAs(100) has been utilized to elucidate the atomic structure of the useful c(4 x 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 x 2)-O interface, provide insight into the atomic structures of oxide/III-V interfaces and a way to control the semiconductor oxidation.

Last updated on 2019-29-01 at 16:22