Novel Design of Nano-Scale Multilayer Reversible ALU Circuit in QCA Technology

In the post-transistor era, QCA technology offers a promising substitute for CMOS technology in VLSI circuits. A crucial component of VLSI circuits is the ALU. The QCA technology has gained popularity due to its ability to minimize energy loss and advantages in device density. Reversible gates in QCA technology are essential for reducing energy loss as heat, facilitating energy-efficient computation. By functioning without dissipating energy, they aid in the advancement of low-power, high-performance computing devices. In this paper, we introduce an improved version of the multilayer Reversible ALU (RALU) utilizing QCA technology. Our objective is to integrate QCA technology with reversible logic to develop a highly efficient ALU. We focus on fundamental elements essential to the design of reversible logic in QCA technology. The advanced ALU integrates various elements that enable it to perform 19 distinct operations. We designed and modeled the proposed QCA RALU structure using QCAD. Simulation results reveal that the circuit is composed of 126 cells, with a delay of 10 clock phases and an area of 0.1042 µm². The developed RALU has an average estimated energy of 5.22 meV and a power dissipation of 0.9 nW. Furthermore, the analysis demonstrates that the developed QCA RALU circuit provides benefits regarding energy use, physical area, processing delay, and cost compared to earlier QCA ALU circuit designs.