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Combinatorial Investigation of Structural Quality of Au/Ni Contacts on GaN



Albert Davydov, Leonid A. Bendersky, William J. Boettinger, Daniel Josell, Mark D. Vaudin, C S. Chang, Ichiro Takeuchi


A combinatorial library of Au/Ni metalizations on GaN were microstructurally characterized by x-ray diffraction (XRD), electron back-scattered diffraction (EBSD) and transmission electron microscopy (TEM). The array of single- and bi-layered metal elements of various thicknesses was deposited by electron-beam evaporation on a GaN/c-sapphire wafer. The single-layered Au elements were polycrystalline and had fiber texture morphology with the [111] orientation normal to the surface. TEM revealed a 2 nm thick native contamination layer at the Au/GaN interface that prevented gold from being epitaxial. By contrast, the single-layered Ni and bi-layered Au/Ni formed epitaxially on the GaN with a (111)fcc//(0001)hex, fcc//hex orientation relation, as observed by TEM and EBSD. The Ni layer adjacent to the GaN formed two types of domains related by 60 rotation about [111]fcc and replicated by the Au over-layer in the Au/Ni structures. The improved structural quality of the bi-layered Au/Ni as compared to the single-layered Au was due to the beneficial role of the nickel inter-layer, which removed native contamination from the GaN surface and promoted epitaxial growth of both metal layers. However, as the nickel inter-layer thickness was increased above 5 nm, the Au/Ni structural quality decreased, as measured by increased deviations from the (111)fcc//(0001)hex orientation relation.
Applied Surface Science
No. 1-3


combinatorial material science, GaN, metal contacts, thin films


Davydov, A. , Bendersky, L. , Boettinger, W. , Josell, D. , Vaudin, M. , Chang, C. and Takeuchi, I. (2004), Combinatorial Investigation of Structural Quality of Au/Ni Contacts on GaN, Applied Surface Science, [online], (Accessed July 15, 2024)


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Created June 1, 2004, Updated February 17, 2017