We Succeeded in growing almost completely relaxed, high-quality, thick GaInN films on an m-plane GaN template with grooves along the < 0 0 0 1 > direction, using lateral-growth technology. Reciprocal space mapping of asymmetrical X-ray diffraction confirmed almost complete relaxation. By transmission electroscopic characterization, the growth of GaInN film with a threading dislocation density of approximately 1 x 10(8) cm(-2) was confirmed. (C) 2008 Elsevier B.V. All rights reserved.