Selective Area Growth of GaN on SiC Substrate by Ammonia-Source MBE

Abstract

The feasibility of selective area growth of GaN by ammonia-MBE has been demonstrated on SiC substrates. Under typical growth conditions for ammonia-MBE, GaN was unable to nucleate on the bare SiC surface. However, GaN nucleation could occur instantly if the SiC surface was first seeded with a thin (300 A) AlN layer prepared by magnetron sputter epitaxy. Thus, GaN growth could occur selectively from a patterned, pre-deposited thin AlN seed layer, and effectively utilizing the exposed SiC surface as a pseudo mask. Evidence of lateral overgrowth was observed by scanning electron microscopy and X-ray diffraction studies. The selectively grown GaN patterns exhibited a strong tendency to form {1011} or {1012} type of facets with excellent smoothness.