SEMICONDUCTOR DEVICE WITH GATE ELECTRODE HAVING METAL NITRIDE AND METHOD FOR FABRICATING THE SAME

摘要

A semiconductor device and its manufacturing method are provided to restrain the generation of a gate depletion by preventing the diffusion of dopants into a channel region of a transistor using an improved gate structure with a metal nitride layer. A semiconductor device comprises a semiconductor substrate(200) with an NMOS transistor region and a PMOS transistor region, an N type gate electrode, and a P type gate electrode. The N type gate electrode(251) is formed on the substrate of the NMOS transistor region. The N type gate electrode is composed of a first conductive pattern and a first polysilicon layer. The P type gate electrode(255) is formed on the substrate of the PMOS transistor region. The P type gate electrode is composed of a second conductive pattern and a second polysilicon pattern. The first and the second conductive patterns include a predetermined metal nitride layer, respectively. The predetermined metal nitride layer contains one selected from a group consisting of W, Mo, Al, Hf and Zr.