TERRACE-WIDTH-INDUCED DOMAIN TRANSITION ON VICINAL SI(100) STUDIED WITH MICROPROBE DIFFRACTION

We have used microprobe RHEED and a convex curved substrate to study the terrace-width dependence of equilibrium surface structures on vicinal Si(001). We observe a transition from double to single domains of the 2 x 1 reconstruction in periodic [110] step arrays that occurs gradually over a range of miscut angle from 0-degrees to 5-degrees, and is independent of temperature over the measured range of 500-800-degrees-C. Possible mechanisms for this transition and its relation to a transition in step heights are described.