Scanning tunneling microscopy study on c(4×4) structure of Si(1 0 0)

We have reexamined the formation and surface structure of Si(1 0 0)-c(4×4) obtained by hydrogen exposure using high resolution scanning tunneling microscopy (STM). The observed filled and empty state STM images are in good agreement with a recent carbon incorporated reconstruction model. We found all of Si dimers present in the c(4×4) unit cell are perpendicular to the underlying Si dimer row. The observation of long line missing dimer defects and SiC islands indicates that the c(4×4) structure observed in this work is also associated to carbon contamination.