Interruption-free growth of 10 μm-thick GaN film prepared on sputtered AlN/PSS template by hydride vapor phase epitaxy

Abstract

GaN films (10μm-thick) of high crystalline quality were prepared on sputtered AlN/PSS template by hydride vapor phase epitaxy (HVPE). By introducing the two-step growth method into HVPE, one can reduce the steps in the procedure, realize uninterrupted growth, and improve the crystal quality of the films. The effects of initial GaN growth on the AlN/PSS template by HVPE were also investigated.In this study, 10μm-thick GaN films prepared on sputtered AlN/PSS template by HVPE showed improved crystal quality using X-ray diffraction and etching pits density. Compared with conventional undoped GaN film grown by metal organic chemical vapor deposition, the full width at half maximum of the (002) and (102) peaks of GaN decreased from 450arcsec to 290arcsec and from 376arcsec to 344arcsec, respectively. Transmission electron microscopy results showed that the gaps observed between the convex regions would eventually turn into dislocations during coalescence, because the number of dislocations increased with the number of gaps observed between the convex regions after step-1 growth.