Growth of crack-free GaN films on Si(111) substrate and improvement of the crystalline quality using SixNy inserting layer

High-quality crack-free GaN films have been grown on 2-inch diameter Si(I 11) substrate using AIN/GaN/AlN stack structure by metalorganic chemical vapor deposition. The dislocation density in GaN overlying layer remarkably reduced when introduce the SixNy inserting layer. The high resolution X-ray diffraction (HRXRD) results of (002) symmetry and (102) asymmetry planes of GaN epilayers show that the dislocation density in GaN epilayer decreases with increasing SixNy growth time. From transmission electron microscope (TEM) measurements, a GaN film with 300 up to 500 s of SixNy deposition time shows that the misfit dislocations almost stop at the SixNy inserting layer. The dislocation density of that sample was similar to 5x10(9) cm(-2). Additionally, a strong band edge emission with FWHM 60 meV was obtained from the room temperature photoluminescence (PL) spectra. (c) 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.