An experiment was carried out to isolate the effect responsible forVocenhancement in back‐surface ion‐implanted Si solar cells. It is shown that open circuit voltage enhancement from back‐surface boron implantation is due to the formation of an effective back surface field rather than to lifetime enhancement that results from damage‐induced gettering. Comparison of boron‐implanted cells is made to cells that had no boron implants and to cells with the boron implant removed by etching.