homoepitaxial

Homoepitaxy is a form of epitaxial growth in which the crystalline film deposited on a substrate is the same chemical species as the substrate. The process aims to reproduce the substrate’s lattice structure in the overlayer, enabling high-crystal-quality layers with minimal lattice mismatch and associated defects.

In homoepitaxy, the film and substrate share the same chemical composition, so lattice parameters are effectively matched, reducing dislocations that arise from lattice mismatch. This contrasts with heteroepitaxy, where differing materials can introduce strain and misfit defects. Even so, defects can arise from surface roughness, impurities, thermal effects, or dopant diffusion during growth.

Common growth methods include molecular beam epitaxy (MBE) and chemical vapor deposition (CVD). In silicon homoepitaxy, precursors such as silane or disilane are used under ultra-high-vacuum or low-pressure conditions, respectively. Substrate preparation usually involves cleaning and oxide removal, followed by heating to the growth temperature. Growth is monitored by techniques such as reflection high-energy electron diffraction (RHEED) in MBE.

Growth modes observed in homoepitaxy include layer-by-layer (Frank–van der Merwe) and, less commonly, island formation under certain conditions. The choice of temperature, pressure, and precursor flux influences surface morphology and dopant incorporation when intentional doping is used.

Applications include the fabrication of high-purity silicon layers for electronic devices, including advanced CMOS structures, as well as research into fundamental epitaxial growth mechanisms. Homoepitaxy provides a controlled platform for studying surface kinetics and dopant behavior in a defect-minimized lattice.