Source engineering for bilayer tunnel field-effect transistor with hetero tunnel junction: thickness and impurity concentration

Abstract

We have investigated the impacts of source layer thickness, source impurity concentration and channel thickness in a bilayer tunneling field-effect transistor with a thin-film hetero tunneling junction on electrical characteristics. Device simulation has revealed that thinning of the source layer significantly degrades on-state current (Ion) due to non-uniform band-to-band tunneling over the tunneling junction, while channel layer thinning is effective for increasing Ion. On the other hand, source/channel impurity concentrations of around 3 × 1018 cm‒3 are found to be optimal for high Ion, high Ion/Ioff and suppression of transfer characteristic shifts with changing Vd.