Morphology of homo-epitaxial vicinal (100) III-V surfaces

Abstract Vicinal substrates are widely used to fabricate semiconductor devices. The different surface step types and their density have a strong influence on the surface structure. We have systematically studied this misorientation dependence on the morphology of (1 0 0)InP as a function of growth conditions in chemical beam epitaxy. On substrates containing no steps or only A-type steps we observe mirror-like surfaces, but many characteristic defects are always present. The defect density is successfully reduced by the introduction of B-type steps. When a sufficient density of only B steps is present, the surface is very smooth with almost no defects. Near any B “step up” edge, however, a ripple pattern is formed, which extends over tens of microns in the B step propagation direction. For substrates with mixed steps the ripple pattern is more pronounced and significant surface roughening occurs. Here, we present and discuss a general model for the morphology of (2×4) reconstructed vicinal (1 0 0) III–V surfaces. It gives a complete and quantitative description of these observations, including the dependence on growth conditions and thus provides a useful tool to study and optimize the growth process.