Patent ID: 8198686

Claim:
A semiconductor device comprising: a first MIS transistor; and a second MIS transistor, wherein: the first MIS transistor includes: a first gate insulating film formed on a first active region in a semiconductor substrate, and including a first high-k film made of oxide containing hafnium and silicon; a first gate electrode including a second metal film formed on the first gate insulating film; first sidewall spacers formed on side surfaces of the first gate electrode, the first sidewall spacers being insulative; and a silicon nitride film formed, extending over the side surfaces of the first gate electrode on which the first sidewall spacers are formed and upper surfaces of regions located in the first active region laterally outside the first sidewall spacers, the second MIS transistor includes: a second gate insulating film formed on a second active region in the semiconductor substrate, and including a second high-k film made of oxide containing hafnium and silicon; a second gate electrode including a first metal film formed on the second gate insulating film and a conductive film formed on the first metal film; second sidewall spacers formed on side surfaces of the second gate electrode, the second sidewall spacers being insulative; the silicon nitride film formed, extending over the side surfaces of the second gate electrode on which the second sidewall spacers are formed and upper surfaces of regions located in the second active region laterally outside the second sidewall spacers; and source/drain regions formed in the second active region laterally outside the second sidewall spacers, the first and second metal films are made of different metal materials, the silicon nitride film is not formed on any of upper surfaces of the first and second gate electrodes, the source/drain regions include a silicon mixed crystal layer which is formed in trenches provided in the second active region, and causes first stress in a gate length direction of a channel region in the second active region, and the silicon nitride film has a thickness smaller than that of the first gate electrode.