Innovative device source/drain and channel implantation for MOS transistors in ultra low power subthreshold circuit applications

摘要

This paper introduces a new comprehensive doping scheme for the transistors in subthreshold circuits. The proposed doping is characterized by the absence of halos at the source and drain ends. We propose a Gaussian doping distribution inside the source and drain regions, and a low-high-low distribution across the depth of the transistor from the channel surface towards the body region. It also has a low-high-low doping distribution along the length of the transistor below the channel region. The analysis is performed by changing the doping densities, body bias and gate-source voltage (Vgs) to observe the variations of off-current (Ioff), threshold voltage and Ion/Ioff ratio. Results show that the optimized device with the proposed doping profile would provide higher drain current (Ion) and Ion/Ioff at a certain body bias.