Fluorine was co‐implanted with 2 MeV erbium into silicon substrates. The thermal treatment for implanted samples was started with a 600 °C, 3 h anneal for solid‐phase epitaxial regrowth then followed by a 900 °C, 30 min anneal to optically activate the erbium atoms. Photoluminescence measurements have shown a strong enhancement of the luminescence intensity in samples co‐implanted with fluorine which, it is suggested, leads to the formation of Er–F complexes and facilitates defect annealing in the silicon lattice. Rutherford backscattering spectrometry was used to characterize the crystalline quality and erbium redistribution after the regrowth. ©1995 American Institute of Physics.