Method for fabricating semiconductor device

A method for fabricating a semiconductor device, comprising the steps of:

• providing a first conductive type semiconductor substrate having a cell region and a logic region defined thereon;
• forming a first insulating film a second conductive type polysilicon, and a second insulating film in succession on the semiconductor substrate;
• selectively removing the second insulating film, and the polysilicon, to form a floating gate pattern at the cell region;
• forming a sidewall oxide film on sidewalls of the floating gate pattern;
• selectively removing the first insulating film by using the second insulating film as a mask after forming the sidewall oxide film;
• forming a gate oxide film on the semiconductor substrate at the logic region;
• and
• forming a gate electrode pattern at each of the cell region and the logic region.

A method for fabricating a semiconductor device, comprising the steps of:

• providing a first conductive type semiconductor substrate having a cell region and a logic region defined thereon;
• forming a first insulating film, and a polysilicon in succession on the semiconductor substrate;
• injecting second conductive type impurity ions into the polysilicon, and forming a second insulating film on the polysilicon;
• selectively removing the first insulating film, the polysilicon, and the second insulating film, to form a floating gate pattern at the cell region;
• forming a gate oxide film on a surface of the semiconductor substrate at the logic region;
• and
• forming a gate electrode pattern at each of the cell region and the logic region.