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HL: Fachverband Halbleiterphysik

HL 45: Group-III-Nitrides: Optical Properties II

HL 45.9: Vortrag

Mittwoch, 24. März 2010, 16:45–17:00, H15

Phase separation in AlGaN layers grown on SiN interlayers — •Kim Juliane Fujan¹, Benjamin Neuschl¹, Ingo Tischer¹, Martin Feneberg¹, Klaus Thonke¹, Martin Klein², Kamran Forghani², and Ferdinand Scholz² — ¹Institut für Halbleiterphysik, Universität Ulm, 89069 Ulm — ²Institut für Optoelektronik, Universität Ulm, 89069 Ulm

For high quality AlGaN templates in-situ SiN interlayers are a possible method to decrease the dislocation density effectively. Immediately after such a SiN layer, the growth re-starts in a 3D-like mode, before the layers smoothen again. We report on a low temperature photoluminescence and cathodoluminescence study with high spatial resolution on a series of such AlGaN layer structures. We find signatures of anisotropic aluminum incorporation efficiency for different facets especially immediately after the interlayer deposition. In cathodoluminescence we directly can spatially resolve this phase separation, which vanishes for layer thicknesses of ∼ 1 µm and more. Influence of layer homogeneity (roughness) and possible growth mechanisms are discussed in detail.