Dresden 2006 – scientific programme
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HL: Halbleiterphysik
HL 50: Poster II
HL 50.16: Poster
Thursday, March 30, 2006, 16:30–19:00, P3
Molecular Beam Epitaxy of cubic AlxGa1−xN and AlN — •Elena Tschumak, Stefan Potthast, Jörg Schörmann, Donat Josef As, and Klaus Lischka — University of Paderborn, Department of Physics, Warburger Strasse 100, D-33095 Paderborn, Germany
Cubic AlxGa1−xN and AlN exhibit a huge potential in the fabrication of electronic and optoelectronic semiconductor devices. In comparison with the hexagonal phase, cubic nitrides show isotropic electrical properties due to the absence of spontaneous piezoelectric fields. In cubic AlN, which has band gap of 5.1eV, the gettered oxygen forms a deep donor level. Therefore, AlN is insulating at room temperature and can be used for electrical insulation of electronic devices on conductive substrate. AlxGa1−xN with a high Al-content is also useful for the fabrication of cubic AlxGa1−xN/GaN Bragg reflectors yielding high reflectivity. AlxGa1−xN-layers with an Al-content between 0.2 and 1 were deposited on 200nm GaN-buffer on 3C-SiC (001) substrates by rf-plasma assisted MBE. The films were grown at temperatures of 750∘C under stoichiometric growth conditions. Growth was in situ monitored by Reflection High-Energy Electron Diffraction (RHEED). Room temperature cathodoluminescence, High Resolution X-Ray Diffraction (HRXRD) and Energy Dispersive X-ray (EDX) measurements were performed to obtain the Al-mole fraction. Surface morphology was studied by Atomic Force Microscope. For the investigation of electrical properties of the AlxGa1−xN-layers, Hall effect was measured between 10-350K.