Patent ID: 7759195
Filing Date: 2010-07-20
Classification: H01L

Abstract:
1. A method for manufacturing a semiconductor device including a first transistor having a composite gate structure and a second transistor having a single gate structure, said method comprising the steps of: forming a first insulating film on a surface of a first region of a semiconductor substrate and forming a second insulating film on a surface of a second region of said semiconductor substrate; forming a first polycrystalline silicon film over an entire surface of said semiconductor substrate; introducing an impurity at a first predetermined concentration into said first polycrystalline silicon film by ion injection; patterning said first polycrystalline silicon film into a predetermined shape in said first region; forming a third insulating film containing at least a silicon nitride film on at least said first region except for said second region of said semiconductor substrate; forming a second polycrystalline silicon film over the entire surface of said semiconductor substrate; introducing an impurity at a second predetermined concentration higher than said first concentration into said second polycrystalline silicon film by thermal diffusion; and patterning a lamination of said second polycrystalline silicon film, said third insulating film and said first polycrystalline silicon film into a predetermined shape in said first region thereby forming said composite gate structure of said first transistor and a lamination of said first polycrystalline silicon film and said second polycrystalline silicon film into a predetermined shape in said second region thereby forming said single gate structure of said second transistor.