A method of manufacturing a semiconductor device includes: forming first to third gate electrodes in first to third regions, respectively; forming a first mask pattern covering the second region while exposing the first and third regions; forming p-type source drain extensions and p-type pocket regions by ion implantation using the first mask pattern as a mask; forming n-type source drain extensions by ion implantation using the first mask pattern as a mask; forming a second mask pattern covering the first and third regions while exposing the second region; and forming p-type pocket regions by implanting ions of indium into the silicon substrate with the second mask pattern being used as a mask.