The Tunnel Field‐Effect Transistor

Abstract

Scaling of metal‐oxide‐semiconductor field‐effect transistors (MOSFET) is hitting fundamental limits due to power issues. In this article, an alternative transistor concept, the tunnel FET (TFET), is discussed, which employs quantum mechanical band‐to‐band tunneling to reduce power consumption. The main operating principle is explained, followed by a discussion of different modeling approaches. Next, the main performance challenges are presented. Different options to overcome these challenges are discussed. These options include a different material choice and alternative implementations, including dopant pockets, improved gate configurations, and strain. Specific considerations for using TFET in a circuit are highlighted. The article concludes with an overview of experimental realizations.

Experimental Details of a Steep-Slope Ferroelectric InGaAs Tunnel-FET With High-Quality PZT and Modeling Insights in the Transient Polarization

“…E NERGY-EFFICIENT logic devices are desired in many application areas, both in conventional hybrid logic applications as well as in internet-of-things applications [1]. Among the candidates to decrease the energy consumption below MOSFET levels, the tunnel-FET (TFET) is a promising device [2]- [4]. It can achieve sub-60mV/dec subthreshold swing (SS) by using the forbidden bandgap to remove the thermal tail of carriers injected in the channel.…”

Compact modeling of intrinsic capacitances in Double-Gate Tunnel-FETs

“…It is comparable with the on-state of a p-type device. In this setting, holes tunnel from drain junction into the channel and rise the I ds [61]. by varying V ds no obvious changes can be seen in I ds .…”

“…Considering the structure of a TFET, the alignment of the electric field which is caused by the gate bias, affects the tunneling direction. In this regard two types of tunneling paths in TFETs are specified: point tunneling and line tunneling[61].…”

“…2(a) illustrates a structure in which tunneling mainly occurs in the corner under the gate oxide at the source-channel junction. In fact, the tunneling paths start from source tunnel junction, bend around the aforementioned corner point and come to an end at the oxide-channel interface[61]. That is the reason why this type of tunneling is known point tunneling.…”

“…2(b), tunneling happens not only around a little point at the corner, but also along the channel. Considering the gate overlap over the source, the tunneling paths are formed as straight lines in the direction of gate electric field, starting from source junction towards the oxide-channel interface.In an ideal case, where the parasitic tunneling at edges and the effect of the drain voltage on the source can be neglected, line-tunneling TFETs show a very abrupt turn-on and also a higher on-current (Ion) in comparison with the point-tunneling TFETs[61,63]. Hence, this structures are attracting attention to be able to overcome the low Ion problem of point-tunneling devices.…”