homoepitaxy

Homoepitaxy is a form of epitaxial growth in which the crystalline layer deposited on a substrate is the same material as the substrate. The resulting film is lattice-registered with the underlying crystal, preserving the same crystal structure and orientation. This contrasts with heteroepitaxy, where the film and substrate are different materials and may involve lattice mismatch and interface complexities.

The process requires a clean, well-characterized crystalline substrate with a suitable surface orientation to promote orderly layer growth. Common deposition methods include molecular beam epitaxy (MBE), chemical vapor deposition (CVD) such as metalorganic or low-pressure variants, and various forms of physical vapor deposition. Doping can be introduced during growth to tailor electrical properties or create specific device structures, such as p–n junctions.

Growth modes in homoepitaxy depend on surface and thermodynamic conditions. Layer-by-layer growth (Frank–van der Merwe) and step-flow growth are typical, while island growth (Volmer–Weber) is less common due to zero lattice mismatch. Since the film and substrate share the same lattice constant, misfit dislocations are far less prevalent than in heteroepitaxy, though defects can arise from substrate quality, thermal stress, or impurities.

Applications of homoepitaxy include the fabrication of high-purity, well-controlled semiconductor layers for devices such as MOS structures and other integrated circuits. The technique enables precise thickness control, sharp interfaces, and tunable doping profiles, contributing to device performance and reproducibility.