Berlin 2012 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 43: Poster Session: Quantum Dots and Wires - Preparation and Characterization / Devices (incl. Laser) / Ultrafast Phenomena

HL 43.19: Poster

Tuesday, March 27, 2012, 09:30–12:30, Poster D

Passivation of ZnO-based MESFETs — •Fabian J. Klüpfel, Stefan Müller, Holger von Wenckstern, and Marius Grundmann — Universität Leipzig, Fakultät für Physik und Geowissenschaften, Abteilung Halbleiterphysik, Linnéstr. 5, 04103 Leipzig

Transparent semiconductors related to ZnO have recently drawn much atttention of the scientific community, e.g. for the application in liquid crystal displays. ZnO-based devices are known to be very sensitive to surface-related effects [1]. The surface termination can for instance lead to highly conductive surface conduction paths [2]. This can be exploited for applications such as gas or chemical sensors. However, to build stable electronic circuits it is neccessary to reach a stable interface, which keeps the electric properties of the device within the desired figures of merit. This can be done by passivating the devices with suitable materials. For thin film transistors based on (Ga,In,Zn)O channels, the usage of the epoxy based photo resist SU-has been proposed [3]. ZnO-based Schottky diodes have been successfully passivated with a CaHfO₃ layer [2]. We could show, that these materials are also suitable for the passivation of (Mg,Zn)O-based metal-semiconducor field-effect transistors. The static device properties could even be enhanced in some cases, while the dynamic properties up to 1 Mhz were not affected. Also the influence on the temperature stability and the avoidance of vacuum induced effects has been investigated.

[1] Allen et al., Trans. Electr. Dev. 56, 2160 (2009)

[2] von Wenckstern et al., J. Elec. Mat. 39, 559 (2009)

[3] Olziersky et al., J. Appl. Phys. 108, 064505 (2010)