Junctionless Sandwiched-gate Logic Design using Novel Device Structure

Abstract

In this paper, a novel sandwiched-gate logic family that is based on a sandwiched-gate inverter, which consists of an NMOS Gate-All-Around (GAA) together with a donut-type PMOS GAA, is proposed. For the realization of the proposed vertical structure, a junctionless configuration is suggested with the absence of the channel- doping process. The ratio of the thickness of the NMOS and the PMOS determines the switching threshold in the sandwiched-gate inverter. The direct-current (DC) operation and the transient performance of the sandwiched-gate inverter are investigated with 3D technology computer-aided-design (TCAD) simulations. The sandwiched- gate inverter exhibits a correct inverter operation with a high noise margin and a fast transition speed. To extend the proposed architecture to other logic gates, the proposed sandwiched-gate structure is also applied to fundamental logic circuits such as the NAND, NOR, and SRAM cell designs, and each operation is verified. The proposed logic gates achieve up to a 20% area reduction compared with the conventional GAA.