Channeling effect measurements were used to evaluate the residual damage in Si after 1000 °C anneal for high‐dose (5×1015−2×1016cm−2) As implantations through oxide layers. For these implantations the amount of damage after anneal increases with As dose and oxide thickness. This residual damage effect was simulated by oxygen implants into Si. We conclude that oxygen recoils are responsible for the disorder found in through‐oxide implants and for defects found at the periphery of oxide cuts used as implantations masks.