Microstructure of low temperature grown AlN thin films on Si„111..

AlN thin films were grown on HF-etched Si~111! substrates at 400– 600 °C by plasma source molecular beam epitaxy. Reflection high energy electron diffraction and transmission electron microscopy studies show that AlN films grown at 400 °C form an initial amorphous region at the interface, followed by c-axis oriented columnar grains with slightly different tilts and twists. AlN films grown at 600 °C showed a significantly reduced amorphous region near the interface promoting an epitaxial growth of AlN with AlN@0001#iSi@111# and AlN@011̄0#iSi@112̄# orientations. However, all the films show numerous defects such as stacking faults, dislocations, and grain boundaries. © 1999 American Institute of Physics. @S0021-8979~99!00611-8#