Nucleation and growth of epitaxial silicon on Si(001) and Si(111) surfaces by scanning tunneling microscopy

The epitaxial growth of silicon on Si(111)-(7×7) and Si(001)-(2×2) substrates at temperatures between 300 and 700 K is studied using scanning tunneling microscopy. On Si(111)-(7×7), the epitaxial islands are triangular and exhibit (7×7)-like reconstructions even at low coverage. STM images show that multilayer growth initiates at boundaries between different (7×7) domains and between (5×5) and (7×7) phases. On Si(001), the epitaxial islands are highly anisotropic, forming long narrow rows only a few dimers wide. Multilayer growth initiates at (2×1) anti-phase boundaries. A model is proposed for the structure at these anti-phase boundaries. © 1989.