Properties of Ir-based Ohmic contacts to AlGaN/GaN high electron mobility transistors

Measurement of the electrical characteristics of 250 devices on the same 2 in. diameter wafer shows that Ti/Al/Ir/Au Ohmic contacts on AlGaN/GaN high electron mobility transistors (HEMTs) have lower average specific contact resistance after annealing at 850 °C for 30 s (4.6×10−5 Ω cm2) compared to m...

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Bibliographic Details
Published in:Applied physics letters 2004-03, Vol.84 (9), p.1495-1497
Main Authors: Fitch, R. C., Gillespie, J. K., Moser, N., Jenkins, T., Sewell, J., Via, D., Crespo, A., Dabiran, A. M., Chow, P. P., Osinsky, A., La Roche, J. R., Ren, F., Pearton, S. J.
Format: Article
Language:English
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Summary:Measurement of the electrical characteristics of 250 devices on the same 2 in. diameter wafer shows that Ti/Al/Ir/Au Ohmic contacts on AlGaN/GaN high electron mobility transistors (HEMTs) have lower average specific contact resistance after annealing at 850 °C for 30 s (4.6×10−5 Ω cm2) compared to more standard Ti/Al/Ni/Au contacts (2×10−4 Ω cm2). HEMTs with these Ir-based contacts also show average interdevice isolation currents approximately a factor of 2 lower, higher peak transconductance (134 mS/mm compared to 121 mS/mm), and higher device breakdown voltage (31 V compared to 23 V) than the devices with Ni-based contacts. This Ir-based contact metallurgy looks promising for applications requiring extended thermal stability of the HEMTs.
ISSN:0003-6951
1077-3118
DOI:10.1063/1.1651649