Berlin 2008 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 51: Poster IV
HL 51.65: Poster
Donnerstag, 28. Februar 2008, 16:30–19:00, Poster D
Optimization of PLD grown ZnO thin films using in-situ RHEED — •Alexander Hirsch, Christian Wille, Frank Ludwig, and Meinhard Schilling — TU Braunschweig, Institut für Elektrische Messtechnik und Grundlagen der Elektrotechnik, Hans-Sommer-Straße 66, D-38106 Braunschweig, Germany
Due to its wide and direct band gap ZnO is an interesting semiconducting material. For application in combination with other oxides a smooth surface is indispensible. In-situ reflection high energy electron diffraction (RHEED) is a powerful tool for optimizing thin film quality.
The ZnO thin films were grown using pulsed laser deposition (PLD) technique. All targets were prepared by standard ceramics synthesis. As substrates Al2O3 in (0001) orientation was used. To obtain atomically flat sapphire surfaces an annealing treatment was applied. The epitaxial growth of the films is investigated by in-situ RHEED supplemented by X-ray diffraction and atomic force microscopy.
The dependence of the PLD parameters on the growth conditions is analyzed. To investigate the influence of the temperature, five thin films at deposition temperatures between 110 ∘C and 820 ∘C were prepared and analyzed. Deposition temperatures of 300 ∘C and 820 ∘C lead to high quality crystalline films with rms roughnesses of approx. 1 nm. Besides, the impact of Al doping on the structural film quality was investigated at a deposition temperature of 300 ∘C. Four thin films with Al concentrations between 0 % and 2 % were grown under equal conditions. In addition, using in-situ RHEED characterization, the effect of interval deposition on the thin film quality was analyzed.