Modeling and analysis of loading effect on leakage of nanoscaled bulk-CMOS logic circuits

In nanoscale complementary metal-oxide-semiconductor (CMOS) devices, a significant increase in subthreshold, gate, and reverse-biased junction band-to-band-tunneling (BTBT) leakage results in large leakage power in logic circuits. Leakage components interact with each other at the device level (through device geometry and the doping profile) and at the circuit level (through the node voltages). Due to the circuit-level interaction of the different leakage components, the leakage of a logic gate depends on the circuit topology, i.e., the number and the nature of the other logic gates connected to its input and output. In this paper, the effect of loading on a leakage of a circuit is analyzed for the first time. The authors have also proposed a method to accurately estimate the total leakage in a logic circuit from its logic-level description considering the impact of loading and transistor stacking.