In a CMOS semiconductor device, low-dose ion implant of p-type impurity and n-type impurity is successively conducted to both n-MOSFET and p-MOSFET after formation of gate electrodes. Thereafter, when source/drain regions are formed at each MOSFET, p.sup.- regions function as local punch through stoppers...http://www.google.com/patents/US5500379?utm_source=gb-gplus-sharePatent US5500379 - Method of manufacturing semiconductor device
