Oxidation of the GaAs semiconductor at the Al 2 O 3 /GaAs junction
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 junc...
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Published in | Physical chemistry chemical physics : PCCP Vol. 17; no. 10; pp. 7060 - 7066 |
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Main Authors | , , , , , , , , , , , , , |
Format | Journal Article |
Language | English |
Published |
2015
|
Online Access | Get full text |
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Summary: | 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 Al
2
O
3
/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 Al
2
O
3
, decreases band-gap defect density at the Al
2
O
3
/GaAs interface. Concomitantly, X-ray photoelectron spectroscopy (XPS) from these Al
2
O
3
/GaAs interfaces shows that the high oxidation state of Ga (Ga
2
O
3
type) decreases, and the corresponding In
2
O
3
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. |
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ISSN: | 1463-9076 1463-9084 |
DOI: | 10.1039/C4CP05972G |