The present disclosure provides a method for preparing a semiconductor memory device with air gaps for reducing capacitive coupling between a bit line and an adjacent conductive feature. The method includes forming an isolation member defining an active region in a substrate and a doped area in the active region; forming a gate structure in the substrate, wherein the gate structure divides the doped are into a first doped region and a second doped region; forming a bit line structure on the first doped region; forming an air gap adjacent to the bit line structure; forming a capacitor plug on the second doped region and a barrier layer on a sidewall of the capacitor plug; and forming a landing pad on a top portion of the capacitor plug, wherein the landing pad comprises a first silicide layer over the protruding portion and a second silicide layer on a sidewall of the barrier layer.