High-Performance Asymmetric Underlap Ge-pTFET With Pocket Implantation

This paper reports a systematic methodology to enhance the performance of germanium p-type tunnel FETs (Ge-pTFETs) using a p
⁺
pocket implant at the source end of the channel and an underlap region at the drain end. The numerical device simulation results show that an optimized drain-underlap region reduces the off-state leakage current (I
_OFF
) of 50-nm Ge-pTFETs to about 3.27 pA/μm without degrading the ON-current (I
_ON
), and a p
⁺
pocket doping improves the ion of these devices to about 0.295 mA/μm without compromising I
_OFF
. The analog and RF performances of the drain-underlapped Ge-pTFETs are investigated in terms of the drain current, transconductance, output resistance, intrinsic gain, cutoff frequency, and maximum frequency of oscillation for pocket-doping length varying from 0 to 6 nm. In addition, the influence of the pocket doping on the nonquasi-static performance is analyzed in terms of the gate-source and gate-drain capacitances, gate-drain resistance, and intrinsic delay time. Finally, the performance of the source-pocket drain-underlapped Ge-pTFETs in ICs is studied using a common source amplifier.