Patent ID: 6531749
Filing Date: 2003-03-11
Classification: H01L

Abstract:
A field effect transistor comprising:a lower gate electrode formed from silicon on a silicon substrate via a gate insulating film; an upper gate electrode formed from copper above said lower gate electrode; a first barrier film having a conductivity capable of supplying to said lower gate electrode a current enough to drive a channel portion and formed to cover a lower surface of said upper gate electrode and impede diffusion of copper, said first barrier film having a thickness of between about 2 nanometers and about 10 nanometers; a second barrier film having a lower end in contact with said first barrier film and formed to cover side surfaces of said upper gate electrode and impede diffusion of copper; a third barrier film having an end portion in contact with said second barrier film and formed to cover an upper surface of said upper gate electrode and impede diffusion of copper; and a source and drain formed in said silicon substrate to sandwich a region under said lower gate electrode, wherein said first barrier film is a multilayered film having at least two layers, wherein said first barrier film is a multilayered film in which a lowermost layer is formed from a layer of a metal silicide or a compound of a refractory metal, silicon, and nitride, and a refractory metal nitride layer is stacked on said metal silicide layer.