GATE STACK STRUCTURE WITH OXYGEN GETTERING LAYER

摘要

A transistor has a channel region in a substrate and source and drain regions in the substrate on opposite sides of the channel region. A gate stack is formed on the substrate above the channel region. This gate stack comprises an interface layer contacting the channel region of the substrate, and a high-k dielectric layer (having a dielectric constant above 4.0) contacting (on) the interface layer. A Nitrogen rich first metal Nitride layer contacts (is on) the dielectric layer, and a metal rich second metal Nitride layer contacts (is on) the first metal Nitride layer. Finally, a Polysilicon cap contacts (is on) the second metal Nitride layer.