Abstract
In situ scanning tunneling microscopy (STM) observations of initial growth processes of GaN by molecular-beam epitaxy reveal important differences between growth on vicinal versus flat SiC(0001) substrates. Based on stop-growth STM studies, we explain why there are orders of magnitude reductions in the density of threading screw dislocations in the vicinal films. It is shown that on vicinal surfaces, three-dimensional (3D) islands develop into a characteristic shape. The islands coalesce much sooner than on flat surfaces. Consequently, fewer defects are created at their boundaries.
- Received 8 March 2001
DOI:https://doi.org/10.1103/PhysRevB.64.033304
©2001 American Physical Society