Experimental band alignment of Ta^sub 2^O^sub 5^/GaN for MIS-HEMT applications

Experimental band alignment of Ta^sub 2^O^sub 5^/GaN for MIS-HEMT applications

The band alignment of Ta2O5/GaN has been measured experimentally. The HCl cleaning has been found to be effective in removing oxygen from the GaN surface and was used prior to deposition of the Ta2O5 films by radio frequency magnetron sputtering. Variable angle spectroscopic ellipsometry was perform...

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Bibliographic Details
Published in:Microelectronic engineering Vol. 178; p. 178
Main Authors: Sawangsri, K, Das, P, Supardan, SN, Mitrovic, IZ, Hall, S, Mahapatra, R, Chakraborty, AK, Treharne, R, Gibbon, J, Dhanak, VR, Durose, K, Chalker, PR
Format: Journal Article
Language:English
Published: Amsterdam Elsevier BV 25-06-2017
Subjects:
Alignment
Band gap
Electrons
Magnetron sputtering
Oxygen
Photoelectron spectroscopy
Spectroellipsometry
Tantalum oxides
Valence band
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Summary:The band alignment of Ta2O5/GaN has been measured experimentally. The HCl cleaning has been found to be effective in removing oxygen from the GaN surface and was used prior to deposition of the Ta2O5 films by radio frequency magnetron sputtering. Variable angle spectroscopic ellipsometry was performed to measure the thickness, optical constants and band gap of GaN and Ta2O5/GaN samples. The valence band offset of Ta2O5/GaN was measured by X-ray photoelectron spectroscopy using Kraut's method, and found to be 0.70 ± 0.25 eV. The results provide experimental evidence of an earlier theoretical study of higher effective barrier for holes than for electrons in the Ta2O5/GaN material system.
ISSN:0167-9317
1873-5568