Semiconductor device and manufacturing method thereof

Abstract

A semiconductor device includes first and second active regions on a semiconductor substrate, separated by an element isolation region; a line-shaped electrode disposed from over the first to over the second active region via the element isolation region; first and second FETs including a gate insulating film on the first and second active regions, respectively, a gate electrode composed of the line-shaped electrode and a source/drain region. Parts of the line-shaped electrode over the first and second active regions are formed of different materials. The line-shaped electrode includes a diffusion restraining region having thickness in a direction perpendicular to the substrate thinner than that over the first and second active regions. The diffusion restraining region is over the element isolation region and spans the whole width of the line-shaped electrode in the gate length direction.