The analysis of the reflection high energy electron diffraction (RHEED) patterns from the vicinal Si(111) (misoriented 1°-6° from [111] to [112]) and (100) surfaces (misoriented 0.4°-4° from [100] to [011]) clarified the differences in step structures on the two surfaces. On the vicinal Si(111) surface, wide terraces with a 7 7 structure and step bunching regions were observed; whereas on the vicinal Si (100) surface, a regular monolayer or bilayer step array was observed. Terrace width and multilayer step height on the vicinal Si (111) surface were estimated by RHEED, scanning electron microscopy, and transmission electron microscopy. The terrace width and multilayer step height were gathered as functions of misorientation angle.