ZrB2 Schottky diode contacts on n-GaN

The annealing temperature dependence of rectifying contact characteristics on epilayers of n-GaN using a ZrB2/Ti/Au metallization scheme deposited by sputtering are reported. A maximum barrier height of 0.57 eV was achieved on samples annealed at 200 deg C, with the reverse breakdown voltage of the...

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Bibliographic Details
Published in:Applied surface science 2006-12, Vol.253 (4), p.2315-2319
Main Authors: Khanna, R, Ramani, K, Cracium, V, Singh, R, Pearton, S J, Ren, F, Kravchenko, I I
Format: Article
Language:English
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Summary:The annealing temperature dependence of rectifying contact characteristics on epilayers of n-GaN using a ZrB2/Ti/Au metallization scheme deposited by sputtering are reported. A maximum barrier height of 0.57 eV was achieved on samples annealed at 200 deg C, with the reverse breakdown voltage of the diodes also a maximum after this anneal. The barrier height was essentially independent of annealing temperature up to 700 deg C even though Auger electron spectroscopy depth profiling showed the onset of inter-contact metallurgical reactions at 500 deg C. The Ti began to outdiffuse to the surface at temperatures of 350 deg C, while the ZrB2/GaN interface showed no evidence of reaction even at 800 deg C. The reverse current magnitude of diodes fabricated using the ZrB2 contacts was larger than predicted by thermionic emission alone.
ISSN:0169-4332
DOI:10.1016/j.apsusc.2006.04.041