A semiconductor device comprising a barrier insulating layer and a related method of fabrication is disclosed. The semiconductor device semiconductor substrate includes a plurality of active regions, wherein active regions are defined by a device isolation layer and are disposed along a first direction; a plurality of bit line electrodes connected to the active regions, wherein each of the bit line electrodes extends along a second direction; and a plurality of first barrier insulating layers. Each of the first barrier insulating layers extends along a third direction, at least one of the first barrier insulating layers is disposed on a corresponding first portion of the device isolation layer disposed between two of the active regions, the two of the active regions are adjacent along the first direction, and the first direction and the second direction differ from one another.