Doping Profile Engineered Triple Heterojunction TFETs With 12-nm Body Thickness

Triple heterojunction (THJ) tunneling field-effect transistors (TFETs) have been proposed to resolve the low ON-current challenge of TFETs. However, the design space for THJ-TFETs is limited by fabrication challenges with respect to device dimensions and material interfaces. This work shows that the original THJ-TFET design with 12-nm body thickness has poor performance because its subthreshold swing (SS) is 50 mV/decade and the ON-current is only 6 mu A/mu m. To improve the performance, the doping profile of THJ-TFET is engineered to boost the resonant tunneling efficiency. The proposed THJ-TFET design shows an SS of 40 mV/decade over four orders of drain current and an ON-current of 325 mu A/mu m with V-GS = 0.3 V. Since THJ-TFETs have multiple quantum wells and material interfaces in the tunneling junction, quantum transport simulations in such devices are complicated. State-of-the-art mode-space quantum transport simulation, including the effect of thermalization and scattering, is employed in this work to optimize THJ-TFET design.

Automated summary

The design of THJ-TFETs addresses the low ON-current challenge of TFETs, but faces limitations due to fabrication challenges with respect to device dimensions and material interfaces. The performance of the original THJ-TFET design is improved by engineering the doping profile to boost resonant tunneling efficiency, resulting in better SS and ON-current. Quantum transport simulations are employed to optimize THJ-TFET design in this study, considering the complexity of devices with multiple quantum wells and material interfaces in the tunneling junction.