A study was made of the reduction of threading dislocations in GaN overlayers grown by organometallic vapor phase epitaxy on micro-porous TiN networks. These networks were obtained by in situ annealing of thin Ti layers deposited in a metallization chamber, on the (0001) face of GaN templates. Observations by transmission electron microscopy indicated dislocation reduction by factors of up to 10 in GaN layers grown on TiN networks compared with the control GaN. X-ray diffraction showed that GaN grown on the TiN network had a smaller (102) plane peak width (4.6arcmin) than the control GaN (7.8arcmin). In low temperature photoluminescence spectra, a narrow excitonic full-width-at-half-maximum of 2.4meV was obtained, as compared to 3.0meV for the control GaN, confirming the improved crystalline quality of the overgrown GaN layers.

Effectiveness of TiN Porous Templates on the Reduction of Threading Dislocations in GaN Overgrowth by Organometallic Vapor-Phase Epitaxy. Y.Fu, Y.T.Moon, F.Yun, Ü.Özgür, J.Q.Xie, S.Doğan, H.Morkoç, C.K.Inoki, T.S.Kuan, L.Zhou, D.J.Smith: Applied Physics Letters, 86[4], 043108 (3pp)