Formation of regular step arrays on Si(111)7×7

Highly regular arrays of steps are produced on vicinal Si(111)7×7 surfaces. A tilt of the surface normal from (111) toward (1̄1̄2) produces single steps (0.3 nm high and typically 15 nm apart). The opposite tilt toward (112̄) produces bunched steps with adjustable height (1–5 nm) and a spacing of 70 nm. Preparation criteria for straight edges and regular spacings are determined, taking into account the miscut angle (azimuthal and polar), annealing sequence, current direction, and applied stress.