Partially recessed dram cell structure

Abstract

A dynamic random access memory (DRAM) cell structure (and method for making a DRAM cell structure) that is more suitable than current DRAM structures for implementation in ever decreasing semiconductor fabrication geometries. The DRAM cell structure comprises a deep trench (DT) capacitor formed in a substrate. A recess is formed in the substrate proximate the deep trench capacitor. A gate is formed that extends into the recess but does not completely occupy the recess. A source is formed in the substrate in a region beneath the recess. A drain is formed in the substrate in a region laterally and vertically offset from the source. A channel between the source and drain is created beneath the gate along a side wall of the recess. Thus, the depth of the recess determines the length of the channel region. With this DRAM cell structure, it is easier to avoid the high doping concentration issue and the short channel effect. Consequently, this DRAM cell structure can be employed with smaller fabrication technologies.