A semiconductor device is formed by depositing a nitride material having a lower etch rate than an oxide material over or between buried gates when forming a metal contact at an end portion of a cell region, to prevent a lower substrate from being etched during an etching process forming a metal contact hole. The semiconductor device includes at least one buried gate formed in a device isolation film of a semiconductor substrate, an etch stop film formed over and between the buried gates, and a metal contact formed perpendicular to the buried gate in the etch stop film.