Epitaxy and characterisation of AlInGaN heterostructures for HEMT application

In this paper we report on the growth and characterization of quaternary AlInGaN/AlN/GaN heterostructures, spanning a range from 26% to 82% AlN, 4% to 18% InN and 0% to 70% GaN in the barrier layer. All samples were grown in AIXTRON metal organic vapor phase epitaxy (MOVPE) reactors on 2'' sapphire substrates. Sample characterisation was performed using high resolution X-ray diffraction (HRXRD), X-ray reflection (XRR), photoluminescence spectroscopy (PL), atomic force microscopy (AFM) and Rutherford backscattering (RBS). Inductive sheet resistance measurements and Hall measurements in van der Pauw geometry provided electrical characterization. AFM measurements show closed layers, in HRXRD measurements pendelloesung oscillations are visible even in asymmetric reciprocal space maps. Mobility and sheet carrier concentration reach state of the art values currently achieved for ternary structures showing the high degree of tunability in the quaternary nitride system. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)