Patent ID: 8710567

Claim:
A semiconductor device comprising: a substrate having a logic region and a random access memory (RAM) region; a first transistor formed in the logic region; and a second transistor formed in the RAM region, wherein said first and second transistors have a stack structure obtained by sequentially stacking a gate insulating film and a metal gate electrode over the substrate, said first transistor has a cap film containing an element selected from a group consisting of lanthanum, ytterbium, magnesium, strontium and erbium as a composition element between said substrate and said metal gate electrode, the first and second transistors have the same conductive type, among the first and second transistors, said cap film is only formed in said first transistor of the logic region and is not formed in said second transistor of the RAM region having the same conductive type as the first transistor, and the gate insulating film at the second transistor has less notching in the gate insulating film in a channel length direction of the second transistor than notching in the gate insulating film at the first transistor in a channel length direction of the first transistor.