A crystallographic model of (00sdot;1) aluminum nitride epitaxial thin film growth on (00sdot;1) sapphire substrate

摘要

Highhyphen;quality thin aluminum nitride films were grown on different orientations of sapphire substrates by metalorganic chemical vapor deposition. (00sdot;1) AlN thin film grown on (00sdot;1) Al2O3has better crystallinity than (11sdot;0) AlN on (01sdot;2) sapphire. Full width at half maximum of a rocking curve is 97.2 arcsec, which is the narrowest value to our knowledge. A crystallographic model between AlN thin films and sapphire substrates was proposed to explain the process of crystal growth. lsquo;lsquo;Extended atomic distance mismatchrsquo;rsquo; which is the mismatch of atomic distance for a longer period was introduced. It is shown that the mismatch is relaxed by edgehyphen;type dislocations. Extended atomic distance mismatch was used to interpret the results that (00sdot;1) AlN has better crystallinity than (11sdot;0) AlN, but (11sdot;0) GaN has better crystallinity than (00sdot;1) GaN.