Impact of Negative Capacitance Field-Effect Transistor (NCFET) on Many-Core Systems [chapter]

Hussam Amrouch, Martin Rapp, Sami Salamin, Jörg Henkel
2020 A Journey of Embedded and Cyber-Physical Systems  
More than a decade ago, the semiconductor technology had entered the so-called nano-CMOS era, in which the transistor's feature sizes became below 90 nm. Since then, the prior trend of voltage scaling came to an end leading to the discontinuation of Dennard's scaling [7] . In Dennard's scaling, both the dimensions of transistor and the operating voltage are typically scaled by the same factor in order to ensure a constant electric field. Due to the non-scalable voltage, ever-increasing power
more » ... sities in chips became a substantial obstacle for technology scaling due to the limited ability of existing cooling solutions to dissipate the generated heat [8] . To overcome this fundamental problem, the maximum frequency of processors had stopped increasing with every new generation in order to keep the on-chip power densities under acceptable levels and since 2005 the era of many-core processors had started. To understand the inability of technology to scale voltage, we need to understand what determines the speed of a processor. As a matter of fact, the drive current (ON current) of a transistor dictates its switching speed and hence it ultimately determines the maximum delay of logic paths that form the processor's netlist. The ON current of a transistor is proportional to (V DD − V T ), where V T denotes the threshold voltage of transistor and V DD denotes the operating voltage. In order to maintain the same level of current, while V DD is scaled down, V T must also be reduced by almost the same amount. However, reducing V T comes with an exponential increase in the leakage current (OFF current) of transistor. This is primarily because that the sub-threshold swing of transistor is fundamentally
doi:10.1007/978-3-030-47487-4_8 fatcat:hva4smvmvredje7hkbyqdyvmdm