Dresden 2006 – wissenschaftliches Programm

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HL: Halbleiterphysik

HL 33: GaN: Preparation and characterization

HL 33.8: Vortrag

Mittwoch, 29. März 2006, 16:15–16:30, BEY 154

Electrical properties of cubic Al_xGa_1−xN/GaN heterostructures — •Stefan Potthast¹, Jörg Schörmann¹, Donat Josef As¹, Klaus Lischka¹, Hiroyuki Nagasawa², and Masayuki Abe² — ¹University of Paderborn, Department of Physics, Warburger Str. 100, 33095 Paderborn, Germany — ²HOYA Advanced Semiconductor Technologies Co., Ltd, 1-17-16 Tanashioda, Sagamihara, Kanagawa 229-1125, Japan

The absence of spontaneous and piezoelectric fields in cubic group-III nitride semiconductors enables the realization of a two-dimensional electron gas (2DEG), whose concentration is independent on the thickness and the Al-content of the barrier material and is adjusted only by the Si-doping of the AlGaN barrier. In this contribution we report on the growth of cubic Al_xGa_1−xN/GaN heterostructures by rf-plasma assisted molecular beam epitaxy on 3C-SiC substrates with an Al-mole fraction between 0.2 and 0.5. Temperature dependent Hall-Effect measurements and CV measurements between 300K and 5K were performed to estimate the electrical properties of the 2-dimensional electron gas, showing a sheet carrier density of 1.6 · 10¹²cm⁻². The carrier density was quantitatively verified by a self consistent solution of the Schrödinger and Poisson equation. Detailed analysis of the electron mobility showed that interface roughness scattering is the dominating scattering process in our structures.