Dresden 2017 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 41: Nitrides: Preparation

HL 41.3: Vortrag

Dienstag, 21. März 2017, 12:15–12:30, POT 06

Investigation of MBE grown AlN and InN layers under the effect of additional Ga acting as a surfactant — •Christopher Hein, Andreas Kraus, Heiko Bremers, Uwe Rossow, and Andreas Hangleiter — Institut für Angewandte Physik, Technische Universität, Braunschweig , Deutschland

Heteroepitaxial growth is always accompanied by misfit strain which, above a certain thickness, leads to relaxation and deterioation of the grown layer. In our work we investigate the surfactant effect of Ga on MBE growth of InN and AlN layers. Templates were 2.5µm thick GaN layers grown in our AIX-200 RF MOVPE on c-oriented sapphire. The 16 nm InN layers were grown at 490^∘C substrate temperature in a double pulsed growth scheme (10s In deposition, 15s nitridation). The AlN samples consist of a previously grown MBE GaN buffer layer, followed by a low temperature AlN interlayer and finally the AlN epilayer in Al pulsed mode. Growth temperatures were 745^∘C for the GaN buffer and AlN epilayer whereas the interlayer was grown at 500^∘C. The comparison samples had an additional Ga flux during their metal pulses. In case of InN using surfactant Ga led to a reduced RMS surface roughness from 4.4 nm down to 2.2 nm (16µm² area) which was accompanied by a remarkable increase of surface coalesence. An increase of structural quality for the AlN layers was observed, as indicated by (0002) and (1010) ω-FWHM reductions from 817” to 766” and 2736” down to 2160” respectively. XRD shows no incorporation of Ga into the epilayers. We will elaborate on the consequences for growth of quantum dot structures on surfaces grown under the influence of a surfactant effect.