Patent ID: 7576397
Filing Date: 2009-08-18
Classification: H01L

Abstract:
1. 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, at least a portion of the first dielectric in contact with the first metal gate electrode being formed with an oxide layer of at least one metal element selected from the group consisting of Zr, Hf, Ti, Ta, Nb, V, Sc, Y, a lanthanoide series and an actinide series; 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 and made of the same material as that of the first metal gate electrode, at least a portion of the second dielectric in contact with the second metal gate electrode being made of an insulating material different from that of at least the portion of the first dielectric in contact with the first metal gate electrode, and at least the portion of the second dielectric in contact with the second metal gate electrode being formed of an oxide layer of the at least one metal element, wherein atomic density of the at least one metal element contained in the first dielectric is 50% or less of atomic density of the at least one metal element contained in the second dielectric.