Electrical and physical characterization of the Al2O3/ p-GaSb interface for 1%, 5%, 10%, and 22% (NH4)2S surface treatments

Peralagu, U. , Povey, I. M., Carolan, P., Lin, J., Contreras-Guerrero, R., Droopad, R., Hurley, P. K. and Thayne, I. G. (2014) Electrical and physical characterization of the Al2O3/ p-GaSb interface for 1%, 5%, 10%, and 22% (NH4)2S surface treatments. Applied Physics Letters, 105(16), 162907. (doi:10.1063/1.4899123)

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Abstract

In this work, the impact of ammonium sulfide ((NH<sub>4</sub>)<sub>2</sub>S) surface treatment on the electrical passivation of the Al<sub>2</sub>O<sub>3</sub>/ <i>p</i>-GaSb interface is studied for varying sulfide concentrations. Prior to atomic layer deposition of Al<sub>2</sub>O<sub>3</sub>, GaSb surfaces were treated in 1%, 5%, 10%, and 22% (NH<sub>4</sub>)<sub>2</sub>S solutions for 10 min at 295 K. The smallest stretch-out and flatband voltage shifts coupled with the largest capacitance swing, as indicated by capacitance-voltage (<i>CV</i>) measurements, were obtained for the 1% treatment. The resulting interface defect trap density (<i>D</i><sub>it</sub>) distribution showed a minimum value of 4 x 10<sup>12</sup> cm<sup>-2</sup>eV<sup>-1</sup> at <i>E</i><sub>v</sub> + 0.27 eV. Transmission electron microscopy and atomic force microscopy examination revealed the formation of interfacial layers and increased roughness at the Al<sub>2</sub>O<sub>3</sub>/ <i>p</i>-GaSb interface of samples treated with 10% and 22% (NH<sub>4</sub>)<sub>2</sub>S. In combination, these effects degrade the interface quality as reflected in the <i>CV</i> characteristics.

Item Type:Articles
Additional Information:Copyright 2014 AIP Publishing. This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing.
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Thayne, Professor Iain and Peralagu, Mr Uthayasankaran
Authors: Peralagu, U., Povey, I. M., Carolan, P., Lin, J., Contreras-Guerrero, R., Droopad, R., Hurley, P. K., and Thayne, I. G.
Subjects:T Technology > TK Electrical engineering. Electronics Nuclear engineering
College/School:College of Science and Engineering > School of Engineering > Electronics and Nanoscale Engineering
Research Group:Micro- and Nanotechnology (Ultrafast Systems)
Journal Name:Applied Physics Letters
Journal Abbr.:Appl. Phys. Lett.
Publisher:American Institute of Physics
ISSN:0003-6951
ISSN (Online):1077-3118
Copyright Holders:Copyright © 2014 American Institute of Physics
First Published:First published in Applied Physics Letters 105(16):162907
Publisher Policy:Reproduced in accordance with the copyright policy of the publisher.

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