The present application discloses a semiconductor device and a method for fabricating the semiconductor device. The semiconductor device includes a substrate; a drain region positioned in the substrate; a common source region positioned in the substrate and opposing to the drain region; a bit line structure including a bit line conductive layer positioned on the substrate and electrically coupled to the common source region; a cell contact positioned on the substrate, adjacent to the bit line structure, and electrically connected to the drain region; a landing pad positioned above the bit line conductive layer and electrically connected to the cell contact; and an air gap positioned between the landing pad and the bit line conductive layer.