The present invention provides a semiconductor device in which the gate is self-aligned to the device isolation film and a fabricating method thereof. A device isolation film restricting an active region is disposed on a portion of a semiconductor substrate, and a word line is across over the device isolation film. A gate pattern is disposed between the word line and the active region, and a tunnel oxide film is disposed between the gate pattern and the active region. The gate pattern comprises a floating gate pattern, a gate interlayer dielectric film pattern and a control gate electrode pattern deposited in the respective order, and has a sidewall self-aligned to the device isolation film. To form the gate pattern having the sidewall self-aligned to the device isolation film, a gate insulation film and a gate material film are formed in the respective order on the semiconductor substrate.