Aluminum Gallium Nitride Alloys Grown via Metalorganic Vapor-Phase Epitaxy Using a Digital Growth Technique

This work investigates the use of a digital growth technique as a viable method for achieving high-quality aluminum gallium nitride (Al (x) Ga1-x N) films via metalorganic vapor-phase epitaxy. Digital alloys are superlattice structures with period thicknesses of a few monolayers. Alloys with an AlN mole fraction ranging from 0.1 to 0.9 were grown by adjusting the thickness of the AlN layer in the superlattice. High-resolution x-ray diffraction was used to determine the superlattice period and c-lattice parameter of the structure, while reciprocal-space mapping was used to determine the a-lattice parameter and evaluate growth coherency. A comparison of the measured lattice parameter with both the nominal value and also the underlying buffer layer is discussed.