METHOD OF FORMING A GATE STRUCTURE IN A SEMICONDUCTOR DEVICE AND METHOD OF FORMING A CELL GETE STRUCTURE IN A NON-VOLATILE MEMORY DEVICE USING THE SAME

摘要

A method for forming a gate structure in a semiconductor device is provided to prevent resistance of a gate from being increased by oxidation of a metal gate electrode by selectively oxidizing a gate oxide layer and a metal gate electrode by a radial oxide method in an atmosphere with rich hydrogen gas during a reoxidation process for curing the gate oxide layer. A preliminary gate structure(121) in which a preliminary gate oxide layer and a metal layer are stacked is formed on a semiconductor substrate(100). The metal layer is made of tungsten, cobalt or titanium. Oxygen-including gas and hydrogen gas are supplied at a flowrate of 1:8 or higher to the resultant structure to control surface oxidation of the metal layer while the oxidation rate of the surface of the metal layer is adjusted to be higher than that the oxidation rate of the surface of the metal layer. The oxygen-including gas can be O2 or O3. During the process for forming the preliminary gate structure, a re-oxidation process for curing the damage of the preliminary gate oxide layer is performed.