SILICON DEPOSITION ON SI(111) SURFACES AT ROOM-TEMPERATURE AND EFFECTS OF ANNEALING

Reflection high energy electron diffraction (RHEED) patterns and rocking curves have been observed during Si deposition onto Si(111)7×7 surface at room temperature. The RHEED pattern changes into δ 7×7 from 7×7 at the initial stage of deposition. From an analysis of the rocking curves and RHEED patterns during the deposition, it is apparent that the backbonds of adatoms of the dimer-adatom-stacking-fault (DAS) structure are broken before completion of the ° 7×7. After the deposition, the surface is annealed at 500 and at 600°C. At both temperatures, a mixed pattern of 7×7 and 5×5 are observed in the RHEED pattern. The domain size of both structures is about 100 Å at the beginning of the annealing. During annealing at 500°C, the 7×7 domain grows gradually with time, while the 5×5 domain size scarcely changes. At 600°C, the 7×7 domain grows rapidly when the 5×5 domain co-exists. Then, the 7×7 domain size increases slowly and the 5×5 structure disappears. The contribution of the 5×5 structure to the epitaxial and the molecular beam epitaxy is discussed. © 1990.