Ngoepe, Phuti Ngako MahlokaMeyer, Walter ErnstAuret, Francois DanieOmotoso, EzekielDiale, M. (Mmantsae Moche)Swart, H.C.Duvenhage, M.M.Coetsee, E.2017-04-202017-04-202016-01Ngoepe, PNM, Meyer, WE, Auret, FD, Omotoso, E, Diale, M, Swart, HC, Duvenhage, MM & Coetsee, E 2016, 'Chemical and electrical characteristics of annealed Ni/Au and Ni/Ir/Au contacts on AlGaN', Physica B : Condensed Matter, vol. 408, pp. 209-212.0921-4526 (print)1873-2135 (online)10.1016/j.physb.2015.08.051http://hdl.handle.net/2263/59994The evolution of Ni/Au and Ni/Ir/Au metal contacts deposited on AlGaN was investigated at different annealing temperatures. The samples were studied with electrical and chemical composition techniques. I-V characteristics of the Schottky diodes were optimum after 500 and 600 ºC annealing for Ni/Au and Ni/Ir/Au based diodes, respectively. The depth profiles of the contacts were measured by x-ray photoelectron spectroscopy and time of flight secondary ion mass spectroscopy. These chemical composition techniques were used to examine the evolution of the metal contacts in order to verify the influence the metals have on the electrical properties of the diodes. The insertion of Ir as a diffusion barrier between Ni and Au effected the electrical properties, improving the stability of the contacts at high temperatures. Gold diffuses into the AlGaN film, degrading the electrical properties of the Ni/Au diode. At 500 ºC, the insertion of Ir, however, prevented the in-diffusion of Au into the AlGaN substrate.en© 2015 Elsevier B.V. All rights reserved. Notice : this is the author’s version of a work that was accepted for publication in Physica B : Consensed Matter. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. A definitive version was subsequently published in Physica B : Consensed Matter, vol. 480, pp. 209-212, 2016. doi : 10.1016/j.physb.2015.08.051.AnnealingSchottky photodiodeAlGaNPostprint Article