Nanofabrication of normally-off GaN vertical nanowire MESFETs Article

Doundoulakis, G, Adikimenakis, A, Stavrinidis, A et al. (2019). Nanofabrication of normally-off GaN vertical nanowire MESFETs . NANOTECHNOLOGY, 30(28), 10.1088/1361-6528/ab13d0

cited authors

  • Doundoulakis, G; Adikimenakis, A; Stavrinidis, A; Tsagaraki, K; Androulidaki, M; Iacovella, F; Deligeorgis, G; Konstantinidis, G; Georgakilas, A


  • Gallium nitride (GaN) all-around (wrap) gate vertical nanowire (V-NW) field-effect transistors (FETs) are favorable for enhanced electrostatic control of the gate and selectivity for normally on/off operation. In this work, GaN V-NW FETs with a Schottky barrier gate (V-NW MESFETs), were fabricated for the first time. A nanofabrication process with comprehensive description of all processing steps is reported. It was validated with the demonstration of GaN V-NW MESFETs consisting of an array of 900 (30 ×30) GaN NWs with the narrowest until now reported diameter of 100 nm and all-around gate length of 250 nm. The GaN NWs were formed by a top-down approach, which combines conventional nanopatterning techniques and anisotropic wet etching of an initial GaN epilayer, grown by plasma assisted molecular beam epitaxy on a sapphire (0001) substrate. DC I-V characteristics exhibited normally-off operation and threshold voltage of +0.4 V, due to electron depletion region from the all-around Schottky barrier. A maximum drain-source current density (J ds) of 330 A cm-2 and maximum transconductance (g m) of 285 S cm-2 were obtained from I-V measurements. The results and directions for further optimization were discussed.

publication date

  • April 25, 2019

published in

Digital Object Identifier (DOI)


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