Method for forming complementary MOS device having asymmetric region in channel region

Claim 1

A method for producing a complementary semiconductor device including: a semiconductor substrate with a principal surface, having a first region doped with an impurity of a first conductivity type and a second region doped with an impurity of a second conductivity type; a first MOS transistor provided on the second region; and a second MOS transistor provided on the first region, the method comprising the steps of: forming a first insulating film and a conductive film on the principal surface of the semiconductor substrate in this order so as to cover the first region and the second region; forming a gate insulating film and a gate electrode of each of the first MOS transistor and the second MOS transistor by patterning the first insulating film and the conductive film; forming a first resist on the principal surface of the semiconductor substrate so as to cover the second region; forming a source region and a drain region of the second MOS transistor, each having the second conductivity type, by implanting impurity ions of the second conductivity type into the first region while using the first resist and the gate electrode of the second MOS transistor as a mask; removing the first resist; forming a second resist on the principal surface of the semiconductor substrate so as to cover the first region; forming a source region and a drain region of the first MOS transistor, each having the first conductivity type, by implanting Impurity ions of the first conductivity type into the second region while using the second resist and the gate electrode of the first MOS transistor as a mask; and forming an asymmetric impurity diffusion region with an asymmetric impurity concentration profile between the source region and the drain region of the first MOS transistor each having the first conductivity type, by obliquely implanting impurity ions of the second conductivity type into the second region while using the second resist and the gate electrode of the first MOS transistor as a mask.

Claim 2

A method for producing a complementary semiconductor device including: a semiconductor substrate with a principal surface, having a first region doped with an impurity of a first conductivity type and a second region doped with an impurity of a second conductivity type; a first MOS transistor provided on the second region; and a second MOS transistor provided on the first region, the method comprising the steps of: forming a first insulating film and a conductive film on the principal surface of the semiconductor substrate in this order so as to cover the first region and the second region; forming a gate insulating film and a gate electrode of each of the first MOS transistor and the second MOS transistor by patterning the first insulating film and the conductive film; forming a first resist on the principal surface of the semiconductor substrate so as to cover the second region; forming a source region and a drain region of the second MOS transistor, each having the second conductivity type, by implanting impurity ions of the second conductivity type into the first region while using the first resist and the gate electrode of the second MOS transistor as a mask; removing the first resist; forming a second resist on the principal surface of the semiconductor substrate so as to cover the first region; forming a source region and a drain region of the first MOS transistor, each having the first conductivity type, by implanting Impurity ions of the first conductivity type into the second region while using the second resist and the gate electrode of the first MOS transistor as a mask; and forming an asymmetric impurity diffusion region with an asymmetric impurity concentration profile between the source region and the drain region of the first MOS transistor each having the first conductivity type, by obliquely implanting impurity ions of the second conductivity type into the second region while using the second resist and the gate electrode of the first MOS transistor as a mask.