Tunneling field effect transistor having a three-side source and fabrication method thereof

Abstract

The present invention discloses a tunneling field effect transistor having a three-side source and a fabrication method thereof, referring to field effect transistor logic devices and circuits in CMOS ultra large scale integrated circuits (ULSI). By means of the strong depletion effect of the three-side source, the transistor can equivalently achieve a steep doping concentration gradient for the source junction, significantly optimizing the sub-threshold slope of the TFET. Meanwhile, the turn-on current of the transistor is boosted. Furthermore, due to a region uncovered by the gate between the gate and the drain, the bipolar conduction effect of the transistor is effectively inhibited, and on the other hand, in the small-size transistor a parasitic tunneling current at the corner of the source junction is inhibited. The fabrication method is simple and can be accurately controlled. By forming the channel region using an epitaxy method subsequent to etching, it facilitates to form a steeper doping concentration gradient for the source region or form a hetero-junction. Moreover, the fabrication flow of the post-gate process facilitates to integrate a high-k gate dielectric/a metal gate having good quality, further improving the performance of the transistor.