E. Richter¹, M. Gründer¹, B. Schineller², F. Brunner¹, U. Zeimer¹, C. Netzel¹, M. Weyers¹, and G. Tränkle¹

Published in:

phys. stat. sol. (c), vol. 8, no. 5, pp. 1450-1454 (2011).

Abstract:

The most promising approach for GaN substrate fabrication on the base of HVPE consists in the growth of thick GaN crystals and subsequent cutting of these boules into slices followed by conventional surface preparation. This work focusses on a HVPE GaN boule growth process optimized to highest growth rate and the use of a commercially available vertical HVPE reactor from AIXTRON in order to develop a technology of high productivity to enable low-cost substrates. To this end, GaN crystals up to thicknesses of 6.3 mm have been grown on 2 inch GaN-on-sapphire templates produced by MOVPE. The rate in HVPE growth was 450 µm/h and the material properties of the crystals have been evaluated. No degradation of the material quality was found by comparison of structural, optical and transport properties with published data of the state of the art of bulk GaN. Dislocation densities as low as 6x10⁵ cm^-2, high electron mobility of 960 cm²/Vs for a carrier density of 1x10¹⁶ cm^-3, low background impurity incorporation of oxygen and silicon, luminescence with well resolved excitonic emission, and a high value of thermal conductivity of 294±44 W/mK were determined.

Keywords:

HVPE, GaN, boule growth, semiconductor properties.

© 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Full version in pdf-format.