Performance Analysis and Optimization of an InGaAs/GaAsSb Heterojunction Dopingless Tunnel FET with a Heterogate Dielectric

An InGaAs/GaAsSb heterojunction dopingless Tunnel FET with a heterogate dielectric is proposed and investigated in this work, aiming to extend the advantages of dopingless TFETs in low-power applications. By employing the InGaAs/GaAsSb heterojunction with a quasi-broken gap energy band structure in dopingless TFET, the HDL-TFET achieves extremely high band-to-band tunneling efficiency. A dual-electrode structure is adopted to improve carrier distribution, which further enhances tunneling efficiency and increases on-state current (I_ON). To suppress off-state tunneling, optimize ambipolar current, and reduce parasitic capacitance, a heterogate dielectric structure is introduced. Results show that the HDL-TFET exhibits an I_ON up to 8.33 × 10^-5 A/μm and a steep subthreshold swing (SS_avg) of 10.18 mV/dec at a low operating voltage of 0.5 V. It also achieves an off-state current (I_OFF) as low as 3.42 × 10^-15 A/μm and I_ON/I_OFF ratio up to 2.44 × 10¹⁰, with no obvious ambipolar current. Compared with previously reported works, the proposed HDL-TFET demonstrates significant advantages. Additionally, the introduction of the heterogate dielectric and dual-electrode structure significantly improves the RF performance of the device, with a peak transconductance (G_m) of 333 μS/μm, and a peak cutoff frequency (f_T) and gain bandwidth product (GBP) up to 64 GHz and 49 GHz, respectively.