The electronic effects and stress effects for epitaxial regrowth rate enhancement in ion‐implanted Si were investigated. By co‐doping B and Ge into Si layers at the same time, the strain field introduced by these impurities in Si can be compensated. Significantly enhanced regrowth rates were obtained in B‐Ge co‐doped and stress‐free Si samples. In contrast, only a slight increase in regrowth rate was observed in the strained Si samples doped only with Ge. These results lead us to conclude that the regrowth rate enhancement of ion‐implanted Si is due mainly to the electronic effects.