A systematic study of (NH4)(2)S passivation (22%, 10%, 5%, or 1%) on the interface properties of the Al2O3/In0.53Ga0.47As/InP system for n-type and p-type In0.53Ga0.47As epitaxial layers
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Date
2011
Authors
O'Connor, Éamon
Brennan, B.
Djara, Vladimir
Cherkaoui, Karim
Monaghan, Scott
Newcomb, Simon B.
Contreras, R.
Milojevic, M.
Hughes, Gregory
Pemble, Martyn E.
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Volume Title
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AIP Publishing
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Abstract
In this work, we present the results of an investigation into the effectiveness of varying ammonium sulphide (NH4)(2)S concentrations in the passivation of n-type and p-type In0.53Ga0.47As. Samples were degreased and immersed in aqueous (NH4)(2)S solutions of concentrations 22%, 10%, 5%, or 1% for 20 min at 295 K, immediately prior to atomic layer deposition of Al2O3. Multi-frequency capacitance-voltage (C-V) results on capacitor structures indicate that the lowest frequency dispersion over the bias range examined occurs for n-type and p-type devices treated with the 10% (NH4)(2)S solution. The deleterious effect on device behavior of increased ambient exposure time after removal from 10% (NH4)(2)S solution is also presented. Estimations of the interface state defect density (D-it) for the optimum 10% (NH4)(2)S passivated In0.53Ga0.47As devices extracted using an approximation to the conductance method, and also extracted using the temperature-modified high-low frequency C-V method, indicate that the same defect is present over n-type and p-type devices having an integrated D-it of similar to 2.5 x 10(12) cm(-2) (+/- 1 x 10(12) cm(-2)) with the peak density positioned in the middle of the In0.53Ga0.47As band gap at approximately 0.37 eV (+/- 0.03 eV) from the valence band edge. Both methods used for extracting D-it show very good agreement, providing evidence to support that the conductance method can be applied to devices incorporating high-k oxides on In0.53Ga0.47As. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3533959]
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Keywords
Capacitance , Ozone , Passivation , Atomic layer deposition , X-ray photoelectron spectroscopy
Citation
O’Connor, É., Brennan, B., Djara, V., Cherkaoui, K., Monaghan, S., Newcomb, S. B., Contreras, R., Milojevic, M., Hughes, G., Pemble, M. E., Wallace, R. M. and Hurley, P. K. (2011) 'A systematic study of (NH4)2S passivation (22%, 10%, 5%, or 1%) on the interface properties of the Al2O3/In0.53Ga0.47As/InP system for n-type and p-type In0.53Ga0.47As epitaxial layers', Journal of Applied Physics, 109(2), 024101 (10pp). doi: 10.1063/1.3533959
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© 2011, American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. The following article appeared in O’Connor, É., Brennan, B., Djara, V., Cherkaoui, K., Monaghan, S., Newcomb, S. B., Contreras, R., Milojevic, M., Hughes, G., Pemble, M. E., Wallace, R. M. and Hurley, P. K. (2011) 'A systematic study of (NH4)2S passivation (22%, 10%, 5%, or 1%) on the interface properties of the Al2O3/In0.53Ga0.47As/InP system for n-type and p-type In0.53Ga0.47As epitaxial layers', Journal of Applied Physics, 109(2), 024101 (10pp). doi: 10.1063/1.3533959 and may be found at http://aip.scitation.org/doi/10.1063/1.3533959