The effects of the layer thickness and of Si doping on the dislocation type and density, electron concentration, and deep trap spectra were studied for epitaxially laterally overgrown GaN films with the epitaxially laterally overgrown region thickness varying from 6 to 12µm. Electron beam induced current imaging showed that for the thickest layers, most of the threading dislocations were filtered out while for thinner films they bend, but did not go out of play. The concentration of

residual donors and major electron traps was found to decrease with increasing the film thickness. Si doping suppresses the concentration of the main electron trap with activation energy of 0.6eV and enhances the concentration of the main hole trap at Ev+0.85eV.

Effects of Laterally Overgrown n-GaN Thickness on Defect and Deep Level Concentrations. A.Y.Polyakov, N.B.Smirnov, A.V.Govorkov, A.V.Markov, E.B.Yakimov, P.S.Vergeles, I.H.Lee, C.R.Lee, S.J.Pearton: Journal of Vacuum Science & Technology B, 2008, 26[3], 990-4