09487 IUPAC Gold Book - epitaxy 10.1351/goldbook.09487 09487 current 1 Deposition of a crystalline over layer on a crystalline substrate. The over layer is called an epitaxial film or epitaxial layer. An ordered spatial relationship existing between the lattices of substrate crystals and those grown by epitaxial crystallization on top of the substrate crystals. Examples involving polymers are given under the terms homoepitaxy and heteroepitaxy, where if the crystals are of the same substance, but possibly different polymorphs, the former term applies, in contrast to the use of the latter term, which involves crystals of two different substances. The term epitaxy is sometimes used for epitaxial crystallization. This use is not recommended. epitaxial crystallization https://goldbook.iupac.org//terms/view/09486 PAC, 2020, 92, 1861. 'Terminology of polymers in advanced lithography (IUPAC Recommendations 2020)' on page 1874 (https://doi.org/10.1515/pac-2018-1215) https://goldbook.iupac.org/terms/view/09487/html https://goldbook.iupac.org/terms/view/09487/json https://goldbook.iupac.org/terms/view/09487/plain Citation: 'epitaxy' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. 10.1351/goldbook.09487 The IUPAC Gold Book is licensed under Creative Commons Attribution-ShareAlike CC BY-SA 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/) for individual terms. If you are interested in licensing the Gold Book for commercial use, please contact the IUPAC Executive Director at executivedirector@iupac.org . The International Union of Pure and Applied Chemistry (IUPAC) is continuously reviewing and, where needed, updating terms in the Compendium of Chemical Terminology (the IUPAC Gold Book). Users of these terms are encouraged to include the version of a term with its use and to check regularly for updates to term definitions that you are using. 2026-07-28T21:24:04+00:00