Monte Carlo simulation for single electron circuits

In single electron circuits composed of small tunnel junctions, capacitances, and voltage sources, a tunneling electron can be described as a discrete charge due to stochastic nature of a tunneling event. We developed a Monte Carlo simulator for the numerical study of single electron circuits because no more conventional simulation methods based on Kirchhoff's laws can be applicable. The calculated dynamic operation of a quasi-CMOS inverter reveals that ultra small load capacitors give rise to large output voltage fluctuation during the logic operation. Future SET circuits should be designed with several electron logic rather than ultimate single electronic logic circuits in which a bit is represented with an electronic charge.