Impact of Negative Capacitance Field-Effect Transistor (NCFET) on Many-Core Systems.

Negative capacitance field-effect transistor (NCFET) is one of the very promising emerging technologies that may replace existing CMOS technology in the future. This is due to its ability to push the sub-threshold swing of transistors to below 60 mV/decade, which what fundamentally limits voltage scaling in conventional CMOS technology and what has led in the past to the discontinuation of Dennard’s scaling. In this chapter, we demonstrate how NCFET technology can reshape the future of many-core systems—especially when it comes to thermally constrained processors. Compared to conventional CMOS technology, NCFET technology allows processors (1) to be clocked at higher frequency without any increase in the power density or (2) to operate at lower voltages, without sacrificing performance requirements. The latter leads to a significant power saving that plays a major role in increasing the total number of processor cores that can be simultaneously powered on without exceeding the predetermined thermal constraints. In addition, we demonstrate how NCFET technology makes the leakage power in processors increase, instead of decrease as in conventional CMOS technology, when voltage is scaled down. This fundamentally breaks down the core assumption of all existing power management techniques. Hence, novel runtime power management techniques need to be devolved in which such a new inverse leakage-voltage dependency is carefully considered. Otherwise, the efficiency of NCFET-based processors cannot be optimized. In this chapter, we also demonstrate the first NCFET-aware dynamic voltage scaling that optimizes the power of processor while taking the inverse leakage-voltage dependency into account.