REVERSAL OF STEP ROUGHNESS ON GE-COVERED VICINAL SI(001)

The influence of Ge on the equilibrium step morphologies of vicinal Si(001) has been investigated quantitatively using scanning tunneling microscopy. As the Ge coverage Ge increases, the relative roughness of the two types of steps on the surface reverses. Physically, the accompanying evolving (2×n) reconstruction modifies the kink energetics by introducing a new type of kink, and confines step meandering. The energies associated with these new kinks and the dependence of the step energies on Ge are extracted. © 1995 The American Physical Society.