Regensburg 2016 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 50: Gallium Nitride: Fabrication and Characterization
HL 50.10: Vortrag
Mittwoch, 9. März 2016, 12:15–12:30, H17
Determination of polarization fields in InAlN/GaN heterostructures by capacitance-voltage-measurements — •Baran Avinc1, Monir Rychetsky1, Konrad Bellman1, Ingrid Koslow1, Tim Wernicke1, Michael Narodovitch1, Michael Lehmann1, Silvio Neugebauer2, Andre Strittmatter2, Bernd Witzigmann3, and Michael Kneissl1 — 1Technische Universität Berlin, Institut für Festkörperphysik, Berlin, Germany — 2Otto von Guericke University Magdeburg, Institute of Experimental Physics, Magdeburg, Germany — 3University of Kassel, Computational Electronics and Photonics Group and CINSat, Kassel, Germany
Lattice-matched InAlN/GaN heterostructures exhibit strong spontaneous polarization fields and sheet charges resulting in band bending. In the literature very few publications exist about the exact field strength values for this material system. In this contribution a new approach to determine polarization fields in nearly lattice-matched InAlN/GaN heterostructures based on capacitance-voltage measurements is used. The change of the polarization fields at the heterointerface influences the charge distribution in a PIN junction and consequently the capacitance. In order to enhance the accuracy of the method we compare the depletion width of two PIN junctions: one with an embedded InAlN layer and therefore influenced by the internal polarization fields, and one without it. The results show an internal field strength of 5.5 MV/cm +/- 1.1 MV/cm for a nearly lattice-matched (nearly 18 % In content) InAlN double heterostructure, in good agreement with theoretically predicted values.