An STM study of Cu on Si(001) in the c(8×8) structure

We have studied the growth of Cu on the Si(001) surface over a range of growth temperatures and metal coverages. The only ordered phase seen by low energy electron diffraction (LEED), other than the 2×1 substrate pattern, was a c(8×8) phase which occurs at coverages as low as 0.05 monolayers. Scanning tunneling microscopy (STM) measurements show that the c(8×8) structure consists of an array of bright features, two per unit cell. We propose one possible atomic structure on the basis of the STM images.