Novel Band-to-Band Tunneling Body Contact (BTBC) Structure to Suppress the Floating- Body Effect in a Vertical-Cell DRAM

A vertical cell is the best structure for optimizing dynamic random access memory size. However, this structure has a fatal weakness called the floatingbody effect (FBE). In this letter, we propose a new vertical structure to suppress FBE and short-channel effects, and successfully demonstrate the structure through simulation. In the new structure, the band-to-band tunnel diode body contact is built in the source region, which effectively releases the accumulated body carriers. In the buried contact, a heavily doped p
⁺
layer is introduced next to the n
⁺
source region, effectively connecting the body and source through tunneling. Furthermore, the proposed structure shows an extremely high ON-state to OFF-state current (ION/IOFF) ratio of ~107 for a channel length of 100 nm.