Abstract: A semiconductor process in which a trench transistor is formed between a pair of planar transistors such that the source/drain regions of the trench transistor are shared with the source/drain regions of the planar transistors. A substrate is provided and first and second planar transistors are formed upon the upper surface of the substrate. The gate dielectric of the trench transistor is vertically displaced below the upper surface of the substrate. The trench transistor shares a first shared source/drain structure with the first planar transistor and a second shared source/drain structure with the second planar transistor. The formation of the trench transistor preferably includes the steps of etching a trench into the substrate, thermally oxidizing a floor of the trench to form a trench gate dielectric, and filling the trench with a conductive material to form a trench gate structure. The trench floor is vertically displaced below the upper surface of the substrate by a trench depth.