The investigation of source doping effect on on-state current in homojunction and heterojunction Tunneling FETs

This paper investigates the influence of source doping effects (SDEs) on the tunneling probability TE(E) and on-state currents in homojunction and heterojunction tunneling FETs (TFETs). A unified formulism in the piecewise two band E-k relationship is applied to analyze SDEs in TFETs with different staggered energy band Δ. Both the analytical and numerical results show that as source doping concentration (N
_s
) increases, TE(E) in homojunction TEFTs increases, while TE(E) in hetero-junction TFETs first increases and then decreases. An optimum source doping concentration (N
_opt
) exists that maximizes the current in heterojunction TFETs, and N
_opt
increases as Δ increases, while current in homojunction TEFTs is not sensitive to the source doping concentration when heavily doped.