Patent ID: 7986014

Claim:
A semiconductor device comprising: a semiconductor substrate; an nMISFET formed on the semiconductor substrate, the nMISFET including a first dielectric formed on the semiconductor substrate and a first metal gate electrode formed on the first dielectric; and a pMISFET formed on the semiconductor substrate, the pMISFET including a second dielectric formed on the semiconductor substrate and a second metal gate electrode formed on the second dielectric, wherein a portion of the first dielectric in contact with the first metal gate electrode and a portion of the second dielectric in contact with the second metal gate electrode include oxygen, a first element of at least one element selected from the group consisting of Zr, Hf, Ti, Ta, Nb, V, Sc, Y, a lanthanoide series and a actinide series, and a second element of at least one element selected from the group consisting of Al, Si and Ge, and an atomic density of the second element in the portion of the first dielectric is higher than an atomic density of the second element in the portion of the second dielectric.