The effects of the damage induced during ion implantation on the surface roughening and oxide growth rate were investigated. Using several scheme of doses and acceleration energies, it is found that the amount of the dose predominantly produce damage rather than the acceleration energy, especially near the surface region. It was also found that the damage affects not only the oxide growth rate but also the surface roughening during high temperature annealing. The edge of highly implanted area may have higher doping concentration due to the vicinal side wall effect of the thick oxide mask for ion implantation. It was confirmed by the trench formation after thermal oxide remove.