Epitaxial growth method and epitaxial silicon wafer which can suppress or prevent impurities in the heavily doped substrate from diffusing to the epitaxial layer

This invention provides an epitaxial growth method and an epitaxial silicon wafer, belonging to the technical field of semiconductor manufacturing. The epitaxial growth method is applied to epitaxial growth equipment. The epitaxial growth equipment includes a reaction chamber and a base located in the reaction chamber. The epitaxial growth method includes: placing a polished silicon wafer on the base; using silicon source gas to sequentially deposit a prefabricated layer and an epitaxial layer on the polished silicon wafer, so that the density of the prefabricated layer is higher than the density of the epitaxial layer.