Low defect density GaN boules were produced using hydride vapor phase epitaxy. A high growth rate of over 100 mum/h enabled the growth of GaN boules longer than 3 mm in length. GaN wafers generated from the boules were characterized by X-ray diffraction, synchrotron white beam X-ray transmission topography, and microscopy of etched surfaces. It was found that the dislocation density decreased with the thickness of the grown material. GaN samples with dislocation density less than 10(4) cm(-2) were produced. The high crystal quality of the GaN samples was further demonstrated with a full-width at half-maximum of 38 arcsec for the GaN(O 0 0 4) double crystal X-ray rocking curve. (C) 2002 Elsevier Science B.V. All rights reserved.