Effect of a buffer layer on GaN growth on a Si(111) substrate with a 3C-SiC intermediate layer

The metalorganic chemical-vapor deposition growth of GaN films on 3C SIC intermediate lavers on Si(111) substrates was carried out using trimethylgallium and NH3. Single crystalline hexagonal GaN layers were grown successfully on Si-terminated SiC intermediate layers by using GaN, AlN, and a superlattice buffer layer. The surface morphology, the crystal quality, and the optical properties of the GaN film with a superlattice as a buffer layer were extremely improved. The GaN films were characterized by using X-ray diffraction, photoluminescence, optical microscopy, scanning electron microscopy, and atomic force microscopy. The minimum full widths at half maximun of the bound exiton peak was 20.39 meV at 5 K and 63.03 meV at 300 K. Also the root-mean-square roughness of the GaN film grown under optimum growth conditions was only 4.21 A.