A significant liability in the use of molecular-beam epitaxy (MBE) to grow device grade compound semiconductor materials is the cost entailed by the necessity of using ultrahigh vacuum and high-growth temperatures. The commercial feasibility of this process could be considerably enhanced if growth temperatures could be cut by one-half or more, In addition, lower growth temperatures could make feasible the growth of semiconductor layers by MBE on top of previously processed structures without degrading or destroying those structures from the high temperatures currently needed for semiconductor growth, An understanding of the detailed atomic nature of this growth process would be valuable in tailoring existing, or developing new techniques towards this end. In the previous papers in this series, we have developed atomic models for various structures on the GaAs( 100) (and related) surfaces used in MBE growth, In this paper, we combine those models to suggest an actual mechanism whereby molecular-beam epitaxy occurs. This proposed mechanism is highly suggestive in terms of improving growth techniques by, for example, varying the incident flux of the constituent species or by using monochromatic light during the growth process. It is foreseen that the implementation of such variations at specific points during the growth cycle may allow substantial reduction in substrate temperature or otherwise improve MBE growth on compound-semiconductor surfaces.

Articles you may be interested inSize and alloying induced changes in lattice constant, core, and valance band binding energy in Pd-Ag, Pd, and Ag nanoparticles: Effect of in-flight sintering temperature

No abstract

We have investigated the structure and composition of the ZnSe(100)c(2×2)–Zn surface. Contrary to prior assumptions, this surface is not terminated with Zn dimers, but, rather with a half monolayer of Zn atoms. This new structure markedly changes our understanding of the growth interface and should lead to better heteroepitaxial growth on this and similar surfaces.

Diffusion in polycrystalline thin films is investigated using both analytical and numerical methods. Bulk, grain-boundary, and interfacial diffusion are all included in the analysis, and the conditions under which each process influences the concentration profile are evaluated. The thin film is treated as a slab of finite thickness containing uniformly spaced grain boundaries that are perpendicular to the plane of the film. One surface of the slab is assumed to be in contact with an infinite reservoir of the diffusing species. Three limiting cases are considered in which the second surface is (i) a barrier to diffusion, (ii) a plane with an infinite surface diffusion coefficient, and (iii) a zero-concentration surface.