In this paper we describe recent experimental efforts to produce high quality thick (≥300 μm) GaN layers on sapphire, the removal of such a layer from the sapphire substrate, and the properties of the so obtained free-standing GaN material. The growth process is described in some detail in the vertical reactor geometry used in this work. Defects like dislocations, micro-cracks and pits produced during growth are discussed, along with procedures to minimize their concentration on the growing surface. The laser lift-off technique is shown to be a feasible technology, in particular if a powerful laser with a large spot size can be used. A major problem with the free-standing material is the typically large bowing of such a wafer, due to the built in defect concentrations near the former GaN-sapphire interface. This bowing typically causes a rather large width of the XRD rocking curve of the free-standing material, while optical data confirm virtually strain free material of excellent quality at the top surface. © 2005 Elsevier B.V. All rights reserved.
CITATION STYLE
Monemar, B., Larsson, H., Hemmingsson, C., Ivanov, I. G., & Gogova, D. (2005). Growth of thick GaN layers with hydride vapour phase epitaxy. In Journal of Crystal Growth (Vol. 281, pp. 17–31). https://doi.org/10.1016/j.jcrysgro.2005.03.040
Mendeley helps you to discover research relevant for your work.