Double-layer stepped Si(1 0 0) surfaces prepared in As-rich CVD ambience

Highlights: • Both (1 × 2) and (2 × 1) reconstructed Si(1 0 0):As surfaces can be prepared by MOCVD. • In situ RAS enables detailed process control even at elevated temperatures. • Si:As surface reactions strongly depend on the Si(1 0 0) substrate misorientation. • Atomically flat low-offcut Si(1 0 0):As-(1 × 2) surfaces with regular double-layer steps. • Arsenic atoms are considered to replace Si atoms during the adsorption process. Low-defect III-V integration on Si(1 0 0) requires atomically well-ordered heterointerfaces. To this end, we study the interaction of As with Si(1 0 0) surfaces and the formation of dimerized Si(1 0 0):As surfaces in situ with reflection anisotropy spectroscopy during metalorganic chemical vapor deposition (MOCVD). Control of surface processes allows us to intentionally 'rotate' the dimer orientation and choose between predominantly (1 × 2) and (2 × 1) reconstructed Si(1 0 0):As surfaces both for low and higher surface misorientation. We also verify that the (2 × 1) surface reconstruction becomes energetically more favorable for vicinal Si(1 0 0):As surfaces. We explain the preparation of Si(1 0 0):As surfaces displaying an almost single-domain, (1 × 2) reconstructed surface with an RMS roughness ≤1 Å and exhibiting broad, atomically flat terraces as well as regular double-layer steps. This surface is highly suitable for subsequent low-defect III-V integration.