Enabling high-performance heterogeneous TFET/CMOS logic with novel circuits using TFET unidirectionality and low-VDD operation

Abstract

Tunneling FETs (TFETs) offer better low-VDD performance than CMOS but lack performance above 0.5V VDD due to low drive current and VDD-dependent parasitic leakages. At low-VDD, TFET's higher energy efficiency enables 2X parallel performance for power constrained systems. For applications less amenable to parallelization, newly proposed circuits improve energy/op, performance and area by not only using TFET's steep sub-threshold swing, but also utilizing its asymmetric IDS-VDS characteristic. Design synthesis with sub-5nm node TFETs, MOSFETs and interconnects is used to assess trade-offs in industry logic blocks. In addition to a 44% energy reduction over CMOS circuits, novel TFET circuits improve dynamic energy by 32% and performance by 13% at logic cell level (4% and 10% respectively at synthesized logic block). Even with these benefits, single-threaded CPUs require CMOS logic's high performance. In this case, heterogeneous TFET/CMOS logic with low-overhead level-shifters improves performance 50% while reducing energy 42% for non-critical performance logic.