Tunneling and intersubband coupling in ultra-thin body double-gate MOSFETs

Deca-nanometer double-gate MOSFETs is studied using a quantum Wigner Monte Carlo approach, including electron-phonon scattering. Intersubband coupling elements are explicitly calculated and proven to be small in doublegate MOSFETs. This allows quantum transport simulations to be analyzed using decoupled subbands. For long gate length the semi-classical result is recovered. An increasing tunneling component of the drain current with decreasing gate length is obtained. The results clearly show the importance of scattering for gate lengths as short as 25 nm. Performance enhancement due to ballistic transport can thereby be estimated.