Floating body dynamic random access memory with enhanced source side capacitance

Abstract

A floating body dynamic random access memory (DRAM) structure has a shallow source (first source portion) and a deep source (second source portion), of which the deep source is thicker. A portion of the floating body extends beneath the shallow source to provide extra capacitance. Optionally, the portion of the floating body beneath the shallow source may be more heavily doped than the depletion zone of the body to further enhance the capacitance. Also, by forming a raised portion of the source without raising the drain, the same implantation energy may be used to dope the raised source and the regular drain. The resulting floating body DRAM structure has an enhanced source to floating body capacitance and stores more charges. Operating margins for write and sense operations are increased and the performance and stability of the floating body DRAM are enhanced.

Dependencies are inferred from the claim text.