Strain relaxation of AlxGa1-xN epitaxial layers on GaN and SiC substrates

摘要

In this article, we present a study on strainrelaxation in AlxGa1-x layers grown by molecular beam epitaxy(MBE) and metalorganic chemical vapor deposition (MOCVD) onthe bulk GaN single crystals (lattice mismatch of -2.5% to 0%)and on the 6R SiC crystals (lattice mismatch of 1% to 3.5%). Bothsynchrotron and X-ray tube radiation were used for diffractometry(double- and triple-axis) and reflectivity measurements. We foundthat the layers on SiC relax easier than those grown on GaN. Theresults show that growth of Al Ga1-x layers on GaN substrates mayprovide a method for producing fully strained (i.e., unrelaxed)blue-laser structures.