Abstract: Growth of GaN film by HVPE was carried out on MOCVD-GaN template and sapphire substrate.The surface of GaN film grown on GaN template was flat and bright,but cracked heavily.The FWHM for GaN (0002) DCXRD is at least 141" .The quality of samples grown directly on sapphire substrate was poor,with a FWHM 1688" for GaN (0002),but it did not crack at all.The carrier gas flow rate was found to have a great effect on pre-reactions.Stress was produced at the interface between the epitaxial layer and the substrate.Holes at the interface can relax the stress greatly,which is helpful for reducing cracks.The yellow luminescence in the PL spectrum arose from O impurity.

Key words: HVPE, GaN, sapphire substrate