METHOD FOR FABRICATING MOSFET OF SEMICONDUCTOR DEVICE

摘要

PURPOSE: A method for fabricating a MOSFET(metal oxide semiconductor field effect transistor) of a semiconductor device is provided to improve a driving speed of a transistor due to a decreased resistance value of a gate electrode by forming a low-resistance gate electrode in which a metal layer is formed on a polysilicon layer without influencing an underlying structure. CONSTITUTION: A gate insulation layer(104), an undoped polysilicon layer and a hard mask layer are sequentially formed on an active region of a semiconductor substrate(100), and are patterned by an etch process using a gate mask. A source/drain region(114) is formed in the substrate. An interlayer dielectric is formed on the resultant structure and is planarized to expose the surface of the hard mask layer. Only the hard mask layer is selectively removed to form a trench. An ion implantation process is performed on the resultant structure to inject dopants into the polysilicon layer. A metal layer is deposited to fill the trench. The meal layer on the interlayer dielectric is removed to form a gate electrode in which the doped polysilicon layer and the metal layer are stacked.