Is the c(4×4) reconstruction of Si(001) associated with the presence of carbon?

Abstract

With the increasing annealing temperature in ultrahigh vacuum, hydrogen-terminated Si(001) surface exhibit a (1×2) reconstruction around 500 °C, c(4×4) in the narrow range of 580–750 °C, and a weak SiC transmission pattern above 750 °C. The simultaneous disappearance of c(4×4) and the appearance of the SiC pattern suggest that the c(4×4) reconstruction is associated with carbon contamination. The carbon concentration of 2.5×1018 atoms/cm3 is insufficient for carbon atoms to be a component of the c(4×4) structure, and therefore the carbon must be having another effect. A consequence of this conclusion is that carbon is not responsible for C-type defects.