Morphology of hnomo-epitaxial vicinal (1 0 0) III-V surfaces

摘要

Vicinal substrates are widely used to fabricte semiconducotr devices. The different surface step types and their density have a strong influence on he surface structure. We have systematically studied this misorientation dependence on the morphology of (1 0 0)InP as a funcion of growth conditons 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 denstiy is successfully reduced by the introduciotn of B-type steps. When a sufficient density of only B steps is present, the surfajce is very smooth with almost no defects. Near any B "jstep up" edge, however, a ripple pattern is formed, which extends over tens of microns in the B sep propagtion direction. For substrates with mixed steps the ripple pattern is more pronounced and signficant surface roughening occurs. Here, we present and discvuss 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 condtions and thus provides a useful tool to study and optimize the grwoth process.