PREPARATION AND PROPERTIES OF FREESTANDING HVPE GROWN GAN SUBSTRATES

In this work, free-standing GaN single crystalline crackless substrate s were grown by hydride vapor phase epitaxy (HVPE). The GaN substrate, having a current maximum size of 350 mu m thickness and 10 mm x 10 mm area, were obtained by the HVPE growth of a thick-film GaN on a sapph ire substrate. Subsequently, the sapphire substrate was removed. To gr ow the crack-free GaN on a sapphire substrate, cracks were intentional ly generated only in the sapphire substrates after 100 mu m thickness GaN growth, and then the GaN thick film was re-grown. The GaN single c rystalline substrate prepared through this work was found to be optica lly and electrically superior to those of bulk GaN single crystals. Th e free-standing and crack-free GaN single crystalline substrate is sui table for the homoepitaxial growth of GaN. (C) 1998 Elsevier Science B .V. All rights reserved.