METHOD FOR MANUFACTURING SEMICONDUCTOR DEVICE

摘要

PURPOSE: A method for manufacturing a semiconductor device is provided to prevent a native oxide and contamination of tungsten in reoxidation processing of a gate and to obtain GGO(Graded Gate Oxide) layer. CONSTITUTION: A gate oxide layer(22) is formed on a semiconductor substrate(20). A stacked gate(200) including the first polysilicon layer(23), a diffusion barrier layer(24) and a tungsten film(25) is formed on the gate oxide layer. A hard mask(26A) is formed on the stacked gate. A tungsten nitride layer(28) is formed at both sidewalls of the tungsten film. The second polysilicon spacer is formed at both sidewalls of the gate and the hard mask. A re-oxide layer(30) is formed by reoxidation processing of the gate using selective oxidation.