A method for fabricating a semiconductor device includes forming a bit line contact hole in a substrate; forming a first spacer on a sidewall of the bit line contact hole; forming a sacrificial spacer over the first spacer; forming a first conductive material that fills the bit line contact hole over the sacrificial spacer; forming a second conductive material over the first conductive material; forming a bit line by etching the second conductive material; and forming a bit line contact plug and a gap between the bit line contact plug and the first spacer by partially etching the first conductive material and the sacrificial spacer to be aligned with the bit line.