GaAsSb/InGaAs heterojunction tunnel field-effect transistors with a heterogeneous channel

Abstract

This study presents a new structure to improve off-state current and ambipolar conduction in GaAsSb/InGaAs heterojunction tunnel field-effect transistors (HTFET). A GaAsSb/InGaAs heterogeneous channel was proposed to form p-GaAsSb/i-InGaAs junction at the source side and i-GaAsSb/n-InGaAs junction at the drain side. In the off-state bias condition, the band offsets of GaAsSb/InGaAs in the channel can prevent electrons tunneling to the drain side to reduce the leakage current and ambipolar conduction. Through simulation, heterogeneous channel HTFETs demonstrate that the off-state current can be reduced by four orders of magnitude and still demonstrate a high on-state current compared with GaAsSb/InGaAs HTFETs. As a result, the proposed heterogeneous channel HTFET exhibits suppressed ambipolar conduction even when the drain doping is as high as 1 ' 10 19 cm %3 .

Analog and RF performance optimization for gate all around tunnel FET using broken-gap material

“…Most of the reports only address one type of geometry and are of mostly MOSFET devices, as the report 12 shows the impact of hydrogen annealing on the device diameter of GAA MOSFET devices, which led to the elliptical circumference having an ON current of 825 µA/µm, report 13 shows the fabricated GAA MOSFET device having an elliptical shape (i.e., EOEC geometry) having ON current of 976 µA/µm, report 15 demonstrate the impact of varying channel length on fabricated elliptical GAA MOSFETs, report 14 demonstrates numerical analysis on three different types of variations such as t si fluctuation, elliptical shape fluctuations (i.e., EOEC fluctuations), and corner rounding fluctuations where the acceptable tolerance for RF IC design is analyzed as Δt si < 1 nm and r/R > 75%, and the report 16 mathematically analyzed the short-channel-effects of elliptical GAA MOSFET (i.e., EOEC structure) by varying its effective radius. The experimental 18 , 19 and numerical analyses 20 suggest that incorporating III-V broken-bandgap semiconductor material in TFET devices shows improved tunnelling efficiency, leading to enhanced device performance 21 , 22 . The ternary compound material of type-II heterostructure such as GaSb/InGaAs gained importance due to its tunable band alignment, direct bandgap, and effective bandgap by varying the mole fraction 23 – 25 .…”