Atomically flat planarization of Ge(100), (110), and (111) surfaces in H2 annealing

Abstract

We demonstrate that Ge(100), (110), and (111) Ge surfaces are planarized with atomic level step and terrace structures in H2 annealing. The temperature required for such planarization is different among the three orientations. The step edge structure on the Ge(100) surface is composed of alternate smooth and rough steps (Sa + Sb steps) owing to the (2 × 1) reconstruction on that surface. It is also shown that the terrace widths on the Ge(110) and (111) surfaces are on average controlled by adjusting the off-angle from the respective surface orientation.