Theoretical investigation of backgate-biasing effects on ultrathin-body GeSn based tunneling FET

Abstract

The impacts of backgate-biasing (KBS) on the performance of ultrathin-body (UTB) GeSn homo- and GeSn/SiGeSn type-II hetero-TFET are investigated via numerical simulation. A negative shift of onset voltage (KONSET) is observed in both devices with KBS varying from −1 V to 1 V. Negative KBS provides higher on-state current (/ON) and steeper subthreshold swing (SS), as compared with the devices under Kbs ≥ 0 V. This is due to the higher carrier generation rate and shorter tunneling path induced by negative KBS. Under the same backgate-bias condition, improved ION, SS, and ambipolar characteristics are demonstrated in the hetero-TFETs over the homo devices.