Patent ID: 7923785
Filing Date: 2011-04-12
Classification: H01L,Y10S

Abstract:
1. A FET situated over a substrate, said FET comprising: a channel situated in said substrate; a first gate dielectric situated over said channel, said first gate dielectric having a first coefficient of thermal expansion; a first gate electrode situated over said first gate dielectric, said first gate electrode having a second coefficient of thermal expansion; wherein said second coefficient of thermal expansion is different than said first coefficient of thermal expansion so as to cause an increase in carrier mobility in said FET; a second gate electrode situated between said first gate electrode and said first gate dielectric, said second gate electrode having a third coefficient of thermal expansion, said third coefficient of thermal expansion being greater than said first coefficient of thermal expansion and said third coefficient of thermal expansion being less than said second coefficient of thermal expansion so as to cause a tensile strain in said channel, said tensile strain causing said increase in said carrier mobility.