A band-to-band tunneling MOS device (B/sup 2/T-MOSFET), which consists of both n/sup +/ source (drain) and p/sup +/ drain (source) is proposed and characterized experimentally in detail. The band-to-band tunneling effect, which puts a new scaling constraint on submicron MOS device design, is used as the mechanism for the operation of this device. Such a diffusion-layer-tunneling device provides no short-channel effects such as V/sub th/ (threshold voltage) lowering and conventional hot-carrier effects, resulting in high scalability down to approximately 0.1 mu m. The electron-hole pairs generated by band-to-band tunneling in the gate-drain overlapped region contribute to the drain current, and high channel doping is not needed. However, it was found that this band-to-band tunneling causes hot-carrier-induced-degradation: V/sub th/ decrease and G/sub m/ (extrinsic transconductance) increase due to hole trapping in n-channel MOSFETs.<<ETX>>