A method for fabricating a semiconductor device includes forming junction area for a bit line contact (BLC) and a junction area for a storage node contact (SNC) by performing ion implantation in a substrate having a buried gate; forming a first insulation pattern having an opening to expose the junction areas; forming a buffer layer to fill the openings; forming a second insulation pattern over the first insulation pattern after filling the openings, wherein the second insulation pattern has openings to expose the buffer layer in an area of the buffer layer that lies over the junction area for the SNC; and forming an SNC to fill the opening of the second insulation patterns.