Microscopic mechanism of the homoepitaxy on Si (111 )7 ×7

摘要: Very initial stages of the homoepitaxy on $\mathrm{Si}(111)7\ifmmode\times\else\texttimes\fi{}7$ surface are studied at 310, 356, and $366{\phantom{\rule{0.16em}{0ex}}}^{\ensuremath{\circ}}\mathrm{C}$ by in situ continuous observation using high-temperature scanning tunneling microscopy (HTSTM) atomic scale during Si deposition under a slow rate 0.02 bilayer $(\mathrm{BL})\phantom{\rule{0.16em}{0ex}}{min}^{\ensuremath{-}1}$. The substrate is reconstructed to well-established dimer-adatom-stacking fault (DAS) structure with $7\ifmmode\times\else\texttimes\fi{}7$ unit cell consisting two triangular half cells (HUCs): stacking faulted (F)-HUC normally stacked one. It expected that complex, large compels proceed quite different manner from unreconstructed surfaces. Formation growth various adsorbed clusters pursued same narrow areas deposition, avoiding tip-shadow effect. most anomalous finding quasiliquid cluster (QLC) spreading plural HUCs (spread QLC) DAS substrate. This appears as result difficulty F-HUC be transformed into BL, being essential for homoepitaxy. After transformation, spread QLC undergoes following structural changes an increase deposition: crystallization small epitaxial BL \ensuremath{\rightarrow} reconstruction structure. Validity reasons transitional formation discussed. mediated mechanism concluded new mode crystal growth. Real HTSTM observations nanoscale indispensable explore dynamic atomistic homoepitaxial $\mathrm{Si}(111)7\ifmmode\times\else\texttimes\fi{}7$.