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HL: Fachverband Halbleiterphysik
HL 28: ZnO: preparation and characterization I
HL 28.6: Vortrag
Mittwoch, 25. März 2009, 11:00–11:15, BEY 118
Design and characterization of ZnO-based MESFETs on glass substrates — •Michael Lorenz, Heiko Frenzel, Holger Hochmuth, Gisela Biehne und 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 Ag as Schottky-gate contact on ZnO thin films grown by pulsed-laser deposition (PLD) on glass substrates. For applications in transparent electronics, the use of cheap glass substrates is more beneficial than sapphire or other crystalline substrates. However, the non-epitaxial growth leads to more structural defects like dislocations, twist and tilt of grain boundaries, and higher surface roughness of the ZnO films. An insulating MgZnO buffer layer was introduced to decrease the influence of such defects on the Al-doped ZnO channel layer. X-ray diffraction, atomic force microscopy as well as Hall-measurements were performed on samples grown at different substrate temperatures between 440∘C and 630∘C and oxygen partial pressures ranging from 0.1 to 3×10−4 mbar. The channel mobilties are at about 1 cm2/Vs and the on/off-ratio is 105. Normally-on and normally-off MESFETs were achieved by adjusting the Al-doping concentration between 0.01% and 0.001%.