The effect ofinsituphotoexcitation during boron ion implantation on subsequent transient enhanced B diffusion in Si has been investigated. Photoexcitation using a mercury arc lamp was performed during B+implantation at 35 keV for a dose of 5×1014cm−2at 177 K. A reduction in the electrical activation dip, i.e., reverse annealing effect, in the temperature range 550–700 °C was observed. Also, the transient enhanced diffusion of B, measured using SIMS following 800 °C, 30 min annealing, was suppressed. Both effects demonstrate that the creation of self‐interstitials during the implantation process is significantly reduced. ©1995 American Institute of Physics.