Method of forming mos transistor having fully silicided metal gate electrode

Abstract

Methods of fabricating a MOS transistor having a fully silicided metal gate electrode are provided. The method includes forming an isolation layer in a predetermined region of a semiconductor substrate to define an active region. An insulated gate pattern which crosses over the active region is formed. A spacer is formed on sidewalls of the gate pattern. A selective epitaxial growth process is applied to form semiconductor layers on the gate pattern and on the active region at both sides of the gate pattern. In this case, a poly-crystalline semiconductor layer is formed on the gate pattern while single-crystalline semiconductor layers are concurrently formed on the active region at both sides of the gate pattern. The semiconductor layers are selectively etched to form a gate-reduced pattern and elevated source and drain regions. Respective desired thicknesses of the gate-reduced pattern and the elevated source and drain regions may be obtained using an etch selectivity between the poly-crystalline semiconductor layer and the single-crystalline semiconductor layer. A silicidation process is applied to the semiconductor substrate where the gate-reduced pattern is formed to simultaneously form a fully silicided metal gate electrode and elevated source and drain silicide layers.