The Influence Of Prestrained Metalorganic Vapor Phase Epitaxial Gallium-Nitride Templates On Hydride Vapor Phase Epitaxial Growth

We have varied the strain situation in metalorganic vapor phase epitaxial (MOVPE) grown gallium-nitride (GaN) by exchanging the nucleation layer and by inserting a submono-SixNy-interlayer in the first few hundred nanometers of growth on sapphire substrates. The influence on the MOVPE template and subsequent hydride vapor phase epitaxial (HVPE) growth could be shown by in-situ measurements of the sample curvature. Using the results of these investigations, we have established a procedure to confine the curvature development in MOVPE and HVPE growth to a minimum. By increasing the layer thickness in HVPE, we could create self-separated, freestanding GaN layers with small remaining curvature. (C) 2014 AIP Publishing LLC.