Semiconductor Physics, Quantum Electronics & Optoelectronics. 2012. V. 15, N 4. P. 351-357.
DOI: https://doi.org/10.15407/spqeo15.04.351

Investigation of resistance formation mechanisms for contacts to n-AlN and n-GaN with a high dislocation density
A.V. Sachenko1, A.E. Belyaev1, N.S. Boltovets2, Yu.V. Zhilyaev3, L.M. Kapitanchuk4, V.P. Klad’ko1, R.V. Konakova1, Ya.Ya. Kudryk1, A.V. Kuchuk1, A.V. Naumov1, V.V. Panteleev3, V.N. Sheremet1

1V. Lashkaryov Institute of Semiconductor Physics, NAS of Ukraine, 03028 Kyiv, Ukraine Phone: 38(044) 525-61-82; fax: 38(044) 525-83-42; e-mail: konakova@isp.kiev.ua
2State Enterprise Research Institute “Orion”, 03057 Kyiv, Ukraine
3Ioffe Physical-Technical Institute, Russian Academy of Sciences, 194021 Sankt-Peterburg, Russia
4Paton Institute of Electric Welding, NAS of Ukraine, 03068 Kyiv, Ukraine

Abstract. . We studied temperature dependences of the resistivity, ρc(T), of Pd-Ti-Pd-Au ohmic contacts to wide-gap semiconductors n-GaN and n-AlN with a high dislocation density. Both ρc(T) curves have portions of exponential decrease, as well as those with very slight ρc(T) dependence at higher temperatures. Besides, the Au-Pd-Ti-Pd-n-GaN contacts have a portion of ρc(T) flattening out in the low-temperature region. This portion appears only after rapid thermal annealing (RTA). In principle, its appearance may be caused by preliminary heavy doping of the near-contact region with a shallow donor impurity as well as doping in the course of contact formation owing to RTA, if the contact-forming layer involves a material atoms of which serve as shallow donors in III-N compounds. The obtained ρc(T) dependences cannot be explained by the existing mechanisms of current transfer. We propose other mechanisms explaining the experimental ρc(T) curves for ohmic contacts to n-GaN and n-AlN.

Keywords: contact resistivity, III-N compounds, dislocation density.

Full Text (PDF)

Back to N4 Volume 15