Regensburg 2010 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 57: Focussed Session: ZnO-based Semiconductors
HL 57.4: Talk
Thursday, March 25, 2010, 15:00–15:15, H17
Dielectric passivated ZnO-based Schottky diodes — •Stefan Müller, Holger von Wenckstern, Zhipeng Zhang, Holger Hochmuth, Michael Lorenz, and Marius Grundmann — Universität Leipzig, Institut für Experimentelle Physik II, Abteilung Halbleiterphysik, Linnéstr. 5, 04103 Leipzig
Vacuum-activated surface conduction (VASC) is a well known phenomenon of ZnO. Concerning ZnO-based devices, it can significantly reduce the parallel resistance of, e.g., Schottky diodes. Therefore, its formation must be suppressed to realize high quality, long-time stable devices. We have recently shown for the case of Au/ZnO Schottky-diodes, that dielectric passivation suppresses a VASC completely[1]. Here, we report on electrical and optical properties of passivated PdOy/ZnO- and PtOy/ZnO-Schottky diodes. The diodes were realized by reactive dc-sputtering of Pd and Pt, respectively, on nominally undoped ZnO thin films grown on a-plane sapphire substrate by pulsed laser deposition (PLD). On those Schottky-diodes a dielectric passivation, e.g. Al2O3 or CaHfO3, was deposited by PLD at room temperature. For optical characterisation, we used depth-resolved cathodoluminescence and light beam induced current measurement, allowing the investigation of the lateral homogenity of the barrier potential on the µ m-scale. Current-voltage- and capacitance-voltage-spectroscopy was measured in a temperature range from 10 K up to the point of thermic degradation and revealed that VASC does not play a role.
[1] H. von Wenckstern et al., J. Electron. Mater., DOI: 10.1007/s11664-009-0974-1