A semiconductor device includes a semiconductor substrate having a first conductivity type and having an upper portion, a pair of bit lines extending in a first direction and doped with an impurity of a second conductivity type opposite to the first conductivity type and spaced from one another in the upper portion of the semiconductor substrate, a first line formed between the pair of bit lines having a plurality of alternating recessed device isolation regions and channel regions, with each of the channel regions contacting each bit line of the at least one pair of bit lines, and word lines formed at right angles to the first lines and covering the channel regions.