The invention provides an
ion implantation method for improving PMOS device performance. The method comprises steps: at least one first
transistor region and at least one second
transistor region separated by an isolation area are formed on a
silicon substrate, a first gate is formed on the first
transistor region, and a second gate is formed on the second transistor region; a
silicon nitride layer is deposited on the
silicon substrate to enable the
silicon nitride layer to fully cover the first transistor region, the second transistor region, the first gate and the second gate; a
photoresist is applied to the silicon substrate to enable the
photoresist to fully cover the first transistor region, the second transistor region, the first gate and the second gate; photoetching is carried out on the
photoresist to remove the photoresist covering the first transistor region and the first gate;
ultraviolet light treatment is carried out on the first transistor region; the photoresist in the second transistor region is removed; and
dry etching is carried out on the
silicon nitride layer so as to form side walls covering two sides of the first gate and side walls covering two sides of the second gate, and side walls at the top part of the gate and the source / drain end are etched and removed.