Semiconductor device and method for manufacturing the same

A method for manufacturing a semiconductor device, comprising:

• forming a p-type semiconductor region and an n-type semiconductor region insulated from each other in a substrate;
• forming a first and second gate insulating films on the p-type and n-type semiconductor regions, respectively;
• forming a first nickel silicide made of one of NiSi2 cubic, NiSi orthorhombic, and Ni2Si orthorhombic on the first gate insulating film, and a second nickel silicide made of at least one of Ni31Si12 hexagonal and Ni3Si cubic on the second gate insulating film;
• and
• segregating aluminum at an interface between the first nickel silicide and the first gate insulating film by diffusing the aluminum through the first nickel silicide.

A semiconductor device comprising:

• a substrate;
• an n-channel MIS transistor including:
• a p-type semiconductor region formed in the substrate;
• first source/drain regions formed at a distance from each other in the p-type semiconductor region;
• a first gate insulating film formed on the p-type semiconductor region between the first source/drain regions;
• a first gate electrode including a first nickel silicide having a composition of Ni/Si<31/12 formed above the first gate insulating film;
• and
• a first aluminum layer segregated at an interface between the first gate insulating film and the first gate electrode;
• and
• a p-channel MIS transistor including:
• an n-type semiconductor region insulated from the p-type semiconductor region and formed in the substrate;
• second source/drain regions formed at a distance from each other in the n-type semiconductor region;
• a second gate insulating film formed on the r-type semiconductor region between the second source/drain regions;
• and
• a second gate electrode including a second nickel silicide having a composition of Ni/Si<31/12 formed above the second gate insulating film, and a third nickel silicide having a composition of Ni/Si≧31/12 formed above the second nickel silicide.