Transistor and method for fabricating the same

A transistor comprising:

• a device isolation oxide film formed on a semiconductor substrate, the device isolation oxide including an opening that exposes a portion of the semiconductor substrate, the exposed portion of the semiconductor substrate defining an active region;
• a gate electrode structure formed in the active region, wherein the gate electrode structure covers only a central portion of the active region and is separated from the device isolation oxide film, the gate electrode structure further comprising
• a gate oxide film formed on the semiconductor substrate in the active region,
• a gate electrode formed on the gate oxide film, the gate electrode having an upper surface and two substantially vertical sidewalls,
• the gate electrode further comprising a stacked structure having a first conductor and a second conductor,
• an oxide layer formed on the first conductor, and
• nitride spacers formed on the oxide layer on the sidewalls of the gate electrode;
• lightly doped drain (LDD) regions formed in the active region of the semiconductor substrate on both sides of the gate electrode;
• source/drain regions formed in the active region of the semiconductor substrate on both sides of the gate electrode;
• and
• second and third insulating films filling and planarizing the space above the active region and between the gate electrode structure and the device isolation oxide film.