Metal-organic hydride vapor phase epitaxy of Al_xGa _1-xN films over sapphire

We present a novel metalorganic hydride vapor phase epitaxy (MPHVPE) approach for lateral epitaxy of high-quality crack-free AlN layers over sapphire with thicknesses in excess of 20 μm. Feasibility of depositing thick AlN buffer layers and device quality Al_xGa_1-xN heterojunctions in a single chamber and growth run using metalorganic chemical vapor deposition and hydride vapor phase epitaxy growths either sequentially or simultaneously is demonstrated. Transmission electron microscopy, atomic force microscopy, and cathodoluminescence analyses confirm the viability of the MGHVPE grown layers for subsequent device fabrication.