Semiconductor device having dual work function gate structure, method for fabricating the same, transistor circuit having the same, memory cell having the same, and electronic device having the same

Abstract

A semiconductor device including a substrate in which a trench is formed, a first impurity region and a second impurity region formed in the substrate separated from each other by the trench, a gate electrode formed to fill a lower part of the trench, and a capping layer formed over the gate electrode to fill an upper part of the trench. The gate electrode includes a first work function liner formed over a bottom surface and sidewalls of the lower part of the trench without overlapping with the first impurity region and the second impurity region, and including an aluminum-containing metal nitride; and a second work function liner formed over the sidewalls of the lower part of the trench over the first work function liner, overlapping with the first impurity region and the second impurity region, and including a silicon-containing non-metal material.