Structural model of Si(100)-c(4 x 4).

Abstract

The $c(4\ifmmode\times\else\texttimes\fi{}4)$ reconstruction of Si(100) clean surface has been obtained by suitable thermal annealing within the temperature range of 580-630\ifmmode^\circ\else\textdegree\fi{}C. The structure transition between $c(4\ifmmode\times\else\texttimes\fi{}4)$ and (2\ifmmode\times\else\texttimes\fi{}1) has been observed. From the experimental result of hydrogen adsorption that the $c(4\ifmmode\times\else\texttimes\fi{}4)$ structure could not convert into (2\ifmmode\times\else\texttimes\fi{}1) or (1\ifmmode\times\else\texttimes\fi{}1) after hydrogen exposure, the buckled dimer arrangement seems unlikely to form such $c(4\ifmmode\times\else\texttimes\fi{}4)$ periodicity. We propose that Pandey's $\ensuremath{\pi}$-bonded defect model with small modification might be a possible model of $c(4\ifmmode\times\else\texttimes\fi{}4)$ reconstruction in explaining all the observed evidences in our experiment.