Semiconductor device

A method for manufacturing a semiconductor device having an nMIS transistor and a pMIS transistor, comprising:

• forming a p-type semiconductor region and an n-type semiconductor region in a surface of a substrate;
• forming a first gate insulating film on the p-type semiconductor region and forming a second gate insulating film on the n-type semiconductor region;
• forming a first metallic film made of a metal material above the first gate insulating film and forming a laminated structure of a second metallic film made of a material having a lower electronegativity than the metal material and a third metallic film made of the metal material above the second gate insulating film;
• performing heat treatment to form a mixed film obtained by mixing the second metallic film and a part of the third metallic film in such a manner that the mixed film comes into contact with the second gate insulating film;
• processing the first metallic film, the third metallic film and the mixed film to have a gate pattern to form a gate electrode for the nMIS transistor above the p-type semiconductor region and form a gate electrode for the pMIS transistor above the n-type semiconductor region,
• wherein a film thickness of the mixed film is one monolayer or more and 3 nm or less, and an average electronegativity of the metal material is larger than an average electronegativity of the mixed film by 0.1 or more.

A method for manufacturing a semiconductor device having an nMIS transistor and a pMIS transistor, comprising:

• forming a p-type semiconductor region and an n-type semiconductor region in a surface of a substrate;
• forming a first gate insulating film on the p-type semiconductor region and forming a second gate insulating film on the n-type semiconductor region;
• forming a laminated structure of a first metallic film made of a metal material and a second metallic film made of a material having a higher electronegativity than the metal material above the first gate insulating film, and forming a laminated structure of a third metallic film made of the metal material and a fourth metallic film made of a material having a lower electronegativity than the metal material above the second gate insulating film;
• performing heat treatment to form a mixed film obtained by mixing the second metallic film and a part of the first metallic film in such a manner that the first mixed film comes into contact with the first gate insulating film and form a second mixed film obtained by mixing the fourth metallic film and a part of the third metallic film in such a manner that the second mixed film comes into contact with the second gate insulating film;
• processing the first metallic film, the third metallic film, the first mixed film and the second mixed film to have a gate pattern to form a gate electrode for the nMIS transistor above the p-type semiconductor region and form a gate electrode for the pMIS transistor above the n-type semiconductor region.