Epitaxial growth of Si on (1012) Al2O3 by partially ionized vapor deposition
Abstract
The epitaxial growth of silicon on (1̄012) sapphire by partially ionized vapor deposition is investigated with a RHEED–AES system. The measurement of the epitaxial temperature and the observation of the RHEED pattern during epitaxial growth are carried out under varying ionization conditions for the silicon ions; i.e., average ion energy of 30 and 180 eV and fractions of silicon ions mixed with silicon atoms ranging from 0 to 7%. When a silicon molecular beam is deposited without ionization for thickness from 2 to 10 nm, (100) oriented and two different {110} oriented islands are observed in the RHEED pattern at substrate temperatures between 870 and 1020 K. The RHEED pattern, however, shows no change for selective epitaxy when the silicon molecular beam is partially ionized up to 7%. A decrease in epitaxial temperature by as much as 150 K is observed at a fraction of silicon ions of 1%, but no further change is observed at higher fractions up to 7% for ion energies of either 30 eV or 180 eV.