Regensburg 2019 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 2: Nitrides: Devices
HL 2.3: Talk
Monday, April 1, 2019, 10:00–10:15, H31
Vertical field-effect transistors based on regular GaN nanostructure arrays — •Klaas Strempel1, Feng Yu1, Friedhard Römer2, Bernd Witzigmann2, Andrey Bakin1, Hergo-Heinrich Wehmann1, Hutomo Suryo Wasisto1, and Andreas Waag1 — 1Institut für Halbleitertechnik (IHT), TU Braunschweig, Germany — 2Computational Electronics and Photonics (CEP), Universität Kassel, Germany
A novel vertical field effect transistor (FET) technology based on 3D GaN nanostructures is introduced, combining the superior material properties of GaN for power electronics with a vertical device architecture and the 3D geometry of nanostructures. Previously realized devices based on top-down etched GaN nanowire arrays achieved promising properties such as normally-off operation, high current densities and excellent electrostatic control over the channel. Here, an improved design based on GaN fins is discussed. Regular fin arrays with smooth a-plane sidewalls were fabricated by a combination of ICP-DRIE and wet chemical etching. The fin dimensions could be precisely controlled via etching and small widths down to 60 nm were achieved. Flexible vertical doping profiles allow the modulation of the channel properties. Nevertheless, the three-dimensionality of the nanostructures increases the complexity of the device processing. Several processing steps have been successfully applied to fabricate vertical GaN FinFETs, including Al2O3 dielectric atomic layer deposition (ALD), inclined electron beam evaporation of the Cr gate, and planarization techniques. Electrical characterization of the devices will be presented.