Investigation of GaSb (p+) Pocket doped GaSb/Si Vertical TFETs for High-Frequency Analog Circuits
摘要
This paper reports on the design, modelling, and performance analysis of a GaSb/Si Heterojunction Vertical Tunnel Field-Effect Transistors (HVTFETs), employing band-to-band tunneling (BTBT). The device structure includes a p+-GaSb source and an intrinsic Si-channel/drain, forming a heterojunction that enhances tunneling efficiency due to the staggered band alignment. The obtained ON and OFF currents are 1 × 10–5 and 1 × 10–18 A/μm. The saturation drain current (IDSat) rises with gate voltage, measured as: 2.7 × 10–8 A for VG = 0.5 V, 3.4 × 10–8 A for VG = 0.6 V and 3.9 × 10–8 A for VG = 0.7 V. The off-state current (IOFF) is very low (~10–19 A) for all the VG values, indicating effective suppression of leakage current. The derived gm values for gate voltages of 0.5, 0.6, and 0.7 V are 5.4 × 10–5, 5.5 × 10–5, and 5.6 × 10–5 S, respectively, indicating effective gate control and transconductive efficiency for signal amplification. The combination of these characteristics would enable high fT and fmax, making the device suitable for broadband and millimeter-wave applications in the radio frequency (RF). The suggested GaSb/Si heterojunction vertical TFET has commendable analog/RF attributes, featuring a peak cutoff frequency (fT) of 8.91 GHz and a maximum oscillation frequency (fmax) of 5.8 GHz. The device demonstrates an intrinsic gain (Av) of 11.2 and a gain-bandwidth product (GBW) of 99.79 GHz, indicating substantial promise for RF front-end applications, including low-noise amplifiers, mixers, and voltage-controlled oscillators, as well as energy harvesting applications.