Dresden 2009 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 37: ZnO: devices

HL 37.3: Talk

Wednesday, March 25, 2009, 16:45–17:00, POT 51

Transport investigations on ZnO-based MESFETs — •Heiko Frenzel, Alexander Lajn, Holger von Wenckstern, Matthias Brandt, Gisela Biehne, Holger Hochmuth, and Marius Grundmann — Universität Leipzig, Fakultät für Physik und Geowissenschaften, Institut für Experimentelle Physik II, Linnéstr. 5, 04103 Leipzig

Metal-semiconductor field-effect transistors (MESFETs) were fabricated by reactive dc-sputtering of either Ag, Pt, Pd, and Au as Schottky-gate contacts on ZnO thin films grown by pulsed-laser deposition on a-plane sapphire substrates. In contrast to ZnO-based metal-insulator field-effect transistors (MISFETs), MESFETs show high dynamics switching within a gate-voltage range of only ±1 V with an on/off-ratio of up to 10⁸ [1]. The channel mobilities are not limited by scattering at the insulator/semiconductor-interface and therefore equal the Hall mobilities of the thin films achieving values up to 27 cm²/Vs. MESFETs comprised of the four most common Schottky metals on ZnO were electrically investigated in a temperature range between 25^∘C and 150^∘C. For Ag, Pt, and Au, the device performance was at least stable until 100^∘C even showing an improvement due to the annealing [2]. Studies of the dependencies on different gate-geometries as well as reliability tests under the influence of light will be presented.

[1] H. Frenzel et al., Appl. Phys. Lett. 92, 192108 (2008)
[2] H. Frenzel et al., Proc. of the 2nd Internat. Symp. on Transparent Conductive Oxides, Thin Solid Films, submitted