Investigation of ambipolar signature in SiGeOI homojunction tunnel FETs

In this paper, we study the ambipolar tunneling signature from the output characteristics of TFETs featuring Si_0.8Ge_0.2 homojunctions, which we compare to those measured on conventional MOSFETs and Schottky Barrier FETs. The difference with the former is immediate since a single TFET can display a transistor effect under both pull-up (nTFET) and pulldown (pTFET) biasing conditions. This is however a property shared with SBFETs, in which injection occurs via tunneling through a single carrier Schottky Barrier instead of band-to-band tunneling. Without requiring quantitative considerations on the current levels or transfer characteristics, we find that simply performing the same dual I_d-V_ds electrical tests while voluntarily "swapping" the S/D terminals unequivocally characterizes TFET operation, even compared to asymmetrically doped SBFETs.