ABSTRACT
The semiconductor industry has devoted much attention to the downscaling of field-effect transistors in the last few decades. The supply voltage (VDD) reduction has become the vital tool to minimize the power density in integrated circuits (ICs). However, the continuous scaling of supply voltage (VDD) has become the major challenge in current CMOS (complementary MOS) technology for ultra low power applications owing to thermal management issue. It is usually believed that the continuing scaling of conventional FETs and its fleaveours like FinFET is limited by the subthreshold swing (SS) that has approached the primordial cap of 60 mV/dec at 300 K due to “Boltzmann Tyranny”, that is, the incapability to eliminate the heat generated in the switching activity. Consequently, the devices with steep subthreshold slope are vital to attain energy-effective switching and low power as VDD scales. The several novel super steep slope FETs, like impact ionization MOS (I-MOS), Z2-FET, tunnel FETs (TFETs), CNFETs, and negative capacitance (NC) FET, have been explored to overcome the “Boltzmann Tyranny”. The TFET and NCFET are two most common super steep slope device in research communities. Tunnel FET is a quantum technical device following band-to-band tunneling as a transport phenomenon, resulting in limited current, suffering ambipolar current, and having a compatibility issue with conventional CMOS circuits and systems. On the other hand, the NCFET integrates a ferroelectric film inside the gate stack of a FET that behaves as a negative capacitance. The coupling of the ferroelectric materials directly with the channel in field-effect transistors provides a unique compatibility with conventional FET devices. An NCFET has the special characteristic that its gate stack isn’t passive and comprises a process for amplification of surface potential. In this chapter, we present the basics of NCFET along with current advancement in the compact modeling field of the NCFET devices in various configurations.
