TFET: From Material to Device Perspective

Due to continuous scaling of the MOS, the performance has been degraded due to PVT variations. The high level of leakage currents, threshold variations, and short-channel effects are responsible toward the degradation of the MOS devices. At this point of time, a device which exhibits low leakage and low subthreshold swing is much needed, and tunnel field-effect transistors (TFETs) reported to be a suitable alternative to MOSFETs. TFETs basically worked on the quantum tunneling effect, and the band-to-band tunneling mechanism is used in which the charge carriers whether electrons or holes pass through a thin energy barrier between the source and the channel regions. It has basically three regions: source, drain, and channel. Semiconductor material like silicon or III–V compounds is used for channel regions. For gate oxide, the dielectric material is used, and choice of high k dielectric material is very crucial. The high dielectric constant materials (high k) are preferred as they help in reducing the tunnel barrier. In this chapter, we have discussed need of TFET devices, their structure type of TFETs along with applications.