Effect of graded InGaN drain region and 'In' fraction in InGaN channel on performances of InGaN tunnel field-effect transistor

摘要

An InGaN-based graded drain region tunnel field-effect transistor (GD-TFET) is proposed to suppress the ambipolar behavior. The simulation results with the trade-off between on-state current (I_(on)) and ambipolar current (I_(ambipolar)) show decreased I_(ambipolar) (1.9 × 1~(-14) A/μm) in comparison with that of conventional TFETs (2.0 × 10~(-8) A/μm). Furthermore, GD-TFET with high 'In' fraction In_xGa_(1-x)N source-side channel (SC- GD-TFET) is explored and exhibits 5.3 times I_(on) improvement and 60% average subthreshold swing (SS_(avg)) reduction in comparison with GD-TFET by adjusting 'In' fraction in the In_xGa_(1-x)N source-side channel. The improvement is attributed to the confinement of BTBT in the source-side channel by the heterojunction. And then, the optimum value for source-side channel length (L_(sc)) is researched by DC performances results, which shows it falls into the range between L_(sc) = 10 nm and 20 nm.