SEMICONDUCTOR DEVICE AND METHOD OF MANUFACTURING THE SAME

A method of manufacturing a semiconductor device, comprising: forming, on a semiconductor substrate a gate insulating film for a high-voltage transistor of a peripheral circuit; forming on the gate insulating film a gate electrode for the high-voltage transistor; removing the gate insulating film positioned on the semiconductor substrate on both side portions of the gate electrode; forming an impurity diffusion region in a surface of the semiconductor substrate; depositing a first silicon oxide film to extend over surfaces of the gate electrode and the impurity diffusion region; etching the first silicon oxide film to form a spacer such that the spacer is formed on a side wall portion of the gate electrode and also extends over the surface of the semiconductor substrate; and forming a silicon nitride film on a surface of the spacer.