Scaling perspectives of ULV microcontroller cores to 28nm UTBB FDSOI CMOS

Short-channel effects and variability in bulk technologies limit the interest of CMOS technology scaling for ultra-low-voltage (ULV) logic below 65nm because of the resulting penalty in the energy efficiency. FDSOI has already been predicted to be a good candidate to keep an excellent energy efficiency while increasing speed at ULV. In this paper, we confirm this result by synthesis results of microcontrollers at 0.35V. We show that the use of a mix of overdrive forward back biasing (FBB) voltages in 28nm FDSOI further improves the energy efficiency. Compare to bulk 65nm CMOS, we were able to reduce the energy per cycle by 64% or increase the frequency of operation by 7x while maintaining energy per operation below 3μW/MHz over a wide frequency range.