US Patent 7485936 Semiconductor device and method of manufacturing the same

It is possible to provide a semiconductor device including a CMOS device having a gate electrode, in which the variation in threshold voltage is little. There are a p-channel MIS transistor and a n-channel MIS transistor which are provided in a semiconductor substrate, and in a region of a gate electrode of the p-channel MIS transistor at least 1 nm or less apart from the interface with a gate insulating film, the oxygen concentration is 1020 cm−3 or more and 1022 cm−3 or less.