T. Okada et al., TRANSMISSION ELECTRON-MICROSCOPY OF SUBLIMATION-GROWN GAN SINGLE-CRYSTAL AND GAN HOMOEPITAXIAL FILM, JPN J A P 2, 35(10B), 1996, pp. 1318-1320
A GaN film with nominal thickness of 0.6 mu m was homoepitaxially depo
sited on a sublimation-grown GaN single-crystal substrate. An electron
-transparent area of 10 mu m x 10 mu m prepared by focused Ga ion beam
machining was examined by transmission electron microscopy. In additi
on to the dislocations on the basal plane of the wurtzite unit cell, a
nother type of dislocation, near pure edge in character and aligned cl
ose to the c-axis direction, was found in the GaN substrate crystal. N
either type of dislocation threaded to the top surface. Dislocation-fr
ee growth was achieved in the GaN homoepitaxial film.