Abstract: This invention relates generally to dynamic random access, semiconductor memory arrays and more specifically relates to an ultra dense dynamic random access memory array. It also relates to a method of fabricating such arrays using a plurality of etch and refill steps which includes a differential etching step which is a key step in forming insulating conduits which themselves are adapted to hold a pair of field effect transistor gates of the adjacent transfer devices of one device memory cells. The differential etch step provides spaced apart device regions and an insulation region of reduced height between the trenches which space apart the memory cells. The resulting structure includes a plurality of rows of vertically arranged field effect transistors wherein the substrate effectively acts as a counterelectrode surrounding the insulated drain regions of each of the one device memory cells. A pair of gates are disposed in insulating conduits which run perpendicular to the rows of memory cells.