A cross‐sectional transmission electron microscope (XTEM) study of solid phase epitaxial growth in BF+2‐implanted (001)Si has been carried out. It is demonstrated that XTEM is unique in providing accurate, high‐resolution data on the regrowth of implantation‐amorphous layer. The activation energy for the regrowth was measured to be 3.0±0.1 eV. Uncertainties in the XTEM measurements of solid phase regrowth rate are discussed.