Chapter 1 - Tunnel FET: Devices and Circuits

Abstract

The superiority of the metal oxide semiconductor field-effect transistor (MOSFET) device over other devices lies in the scalability of these devices. However, the channel length scaling of MOSFETs has resulted in enormous energy dissipation in conventional complementary metal oxide semiconductor technology. It means, successive technologies cannot be continued with scaling of the MOSFETs for improved performance. Therefore, transistors with reduced energy dissipation have become an interesting research topic for future technologies. In this chapter, a tunneling field-effect transistor (TFET) that works on the principle of band-to-band tunneling (BTBT) is introduced. TFETs have potential to reduce the power consumption of the Integrated circuits (ICs). Scaling of supply voltage reduces the required switching energy; however, the fundamental limit of the subthreshold slope (SS)=60mV/dec is a major obstacle in scaling of the supply voltage. TFETs overwhelm this SS limit and allow the scaling of the supply voltage. Although TFETs reduce the power dissipation of the device, the circuit design has remained a challenge due to its ambipolar characteristics, low ON current (ION), and asymmetric current flow through the device. Techniques to improve the ambipolar current, ION, and circuit design methodology with asymmetric devices are discussed in this chapter. Heterojunction and III–V semiconductors are the two major techniques that allow a band gap engineering to improve the performance of the TFETs. Therefore, a brief discussion of the III–V semiconductor-based TFETs and their circuit design parameters are also covered in this chapter.