Relative performance of three nanoscale devices - CMOS, RTDs and QCAs - against a standard computing task

We present results to show the effects of device scaling on the relative performance of three device technologies, namely resonant tunnelling diodes (RTD), electronic quantum cellular automata (QCA) and complementary metal-oxide-semiconductor (CMOS) transistor technology. The minimum feature size (MOSFET or HFET gate lengths λ) is scaled from 250 to 50 nm, while QCA inter-dot separations of 20 to 2 nm are examined. The comparison is made using a standard digital circuit architecture, namely a memory-adder model. Our aim is to compare these device technologies on the system level rather than individual device level. The results show that the RTDs offer speed advantages over CMOS, but improvements in the circuit density are limited. The electronic QCAs will suffer both from effectively low packing density and low operating speeds in comparison to CMOS if conventional designs and a 2D architecture are used.