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HL: Halbleiterphysik

HL 44: Poster II

HL 44.79: Poster

Donnerstag, 11. März 2004, 16:30–19:00, Poster A

Characterization of crack-free and relaxed bulk-like GaN grown on 2” sapphire — •A. Kasic¹, D. Gogova¹, H. Larsson¹, C. Hemmingsson¹, I. Ivanov¹, B. Monemar¹, C. Bundesmann², M. Schubert², and M. Heuken³ — ¹Linköping University, Department of Physics and Measurement Technology, S-581 83 Linköping, Sweden — ²Universität Leipzig, Institut für Experimentelle Physik II, Linnéstr. 5, D-04103 Leipzig — ³Aixtron AG, Kackerstraße 15-17, D-52072 Aachen

We demonstrate the growth of high-quality and stress-free bulk-like (300-µ m-thick) GaN by hydride vapor phase epitaxy (HVPE) in a vertical atmospheric-pressure reactor. The crystalline quality and the residual stress in the 2” GaN wafer were investigated by various characterization techniques. The lateral homogeneity of the wafer was monitored by low-temperature photoluminescence mapping. Precise µ -Raman scattering profiling measurements provide the vertical strain distribution and the evolution of the crystalline quality with increasing film thickness. The high crystalline quality on the Ga-face was proved by high-resolution X-ray diffraction and photoluminescence measurements. The position of the main near-band-gap photoluminescence line and the phonon spectra obtained by infrared spectroscopic ellipsometry show consistently that the 2” crack-free GaN is virtually stress-free over a diameter of approximately 4 cm.

Such GaN material can serve as a substrate for further homoepitaxial strain-relaxed and crack-free growth needed for fabrication of device structures.