AlN films deposited on SiC or sapphire substrates by pulsed laser depositio
n were annealed at 1200 degrees C, 1400 degrees C, and 1600 degrees C for 3
0 min in an inert atmosphere to examine how their structure, surface morpho
logy, and substrate-film interface are altered during high temperature ther
mal processing. Shifts in the x-ray rocking curve peaks suggest that anneal
ing increases the film density or relaxes the films and reduces the c-axis
Poisson compression. Scanning electron micrographs show that the AlN begins
to noticeably evaporate at 1600 degrees C, and the evaporation rate is hig
her for the films grown an sapphire because the as-deposited film contained
more pinholes. Rutherford backscattering spectroscopy shows that the inter
face between the film and substrate improves with annealing temperature for
SiC substrates, but the interface quality for the 1600 degrees C anneal is
poorer than it is for the 1400 degrees C anneal when the substrate is sapp
hire. Transmission electron micrographs show that the as-deposited films on
SiC contain many stacking faults, while those annealed at 1600 degrees C h
ave a columnar structure with slightly misoriented grains. The as-deposited
films on sapphire have an incoherent interface, and voids are formed at th
e interface when the samples are annealed at 1600 degrees C. Auger electron
spectroscopy shows that virtually no intermixing occurs across the interfa
ce, and that the annealed films.