Critical Issues in Oxide-Semiconductor Heteroepitaxy

Abstract

In this chapter, we focus on the specific features and challenges that set oxide-semiconductor heteroepitaxial systems apart from the more commonly discussed cases of semiconductor-semiconductor and oxide-oxide epitaxy. Here we focus on the fundamental issues of the oxide/semiconductor epitaxy, using SrTiO₃ on Si and GaAs as examples. The fundamental difficulty of perovskite/semiconductor epitaxy lies in thermodynamics. To achieve layer-by-layer growth, the film should wet the substrate. Wetting is controlled at the microscopic level by the interatomic forces. Even if the issues concerning lattice matching and wetting have somehow been resolved, the success of an epitaxial growth process is still dependent on an even more basic issue: thermodynamic stability of the film when in contact with the substrate at the growth conditions. A good atomic-scale understanding of the materials system is shown to be necessary, which highlights the importance of the use of microscopic theory in this field.