A 2x2 bit multiplier using hybrid 13t full adder with vedic mathematics method

Various arithmetic circuits such as multipliers require full adder (FA) as the main block for the circuit to operate. Speed and energy consumption become very vital in design consideration for a low power adder. In this paper, a 2x2 bit Vedic multiplier using hybrid full adder (HFA) with 13 transistors (13T) had been designed successfully. The design was simulated using Synopsys Custom Tools in General Purpose Design Kit (GPDK) 90 nm CMOS technology process. In this design, four AND gates and two hybrid FA (HFAs) are cascaded together and each HFA is constructed from three modules. The cascaded module is arranged in the Vedic mathematics algorithm. This algorithm satisfied the requirement of a fast multiplication operation because of the vertical and crosswise architecture from the Urdhva Triyakbyam Sutra which reduced the number of partial products compared to the conventional multiplication algorithm. With the combination of hybrid full adder and Vedic mathematics, a new combination of multiplier method with low power and low delay is produced. Performance parameters such as power consumption and delay were compared to some of the existing designs. With a 1V voltage supply, the average power consumption of the proposed multiplier was found to be 22.96 µW and a delay of 161 ps

Simulation study of scaling design, performance characterization, statistical variability and reliability of decananometer MOSFETs

This thesis describes a comprehensive, simulation based scaling study – including device design, performance characterization, and the impact of statistical variability – on deca-nanometer bulk MOSFETs. After careful calibration of fabrication processes and electrical characteristics for n- and p-MOSFETs with 35 nm physical gate length, 1 nm EOT and stress engineering, the simulated devices closely match the performance of contemporary 45 nm CMOS technologies. Scaling to 25 nm, 18 nm and 13 nm gate length n and p devices follows generalized scaling rules, augmented by physically realistic constraints and the introduction of high-k/metal-gate stacks. The scaled devices attain the performance stipulated by the ITRS. Device a.c. performance is analyzed, at device and circuit level. Extrinsic parasitics become critical to nano-CMOS device performance. The thesis describes device capacitance components, analyzes the CMOS inverter, and obtains new insights into the inverter propagation delay in nano-CMOS. The projection of a.c. performance of scaled devices is obtained. The statistical variability of electrical characteristics, due to intrinsic parameter fluctuation sources, in contemporary and scaled decananometer MOSFETs is systematically investigated for the first time. The statistical variability sources: random discrete dopants, gate line edge roughness and poly-silicon granularity are simulated, in combination, in an ensemble of microscopically different devices. An increasing trend in the standard deviation of the threshold voltage as a function of scaling is observed. The introduction of high-k/metal gates improves electrostatic integrity and slows this trend. Statistical evaluations of variability in Ion and Ioff as a function of scaling are also performed. For the first time, the impact of strain on statistical variability is studied. Gate line edge roughness results in areas of local channel shortening, accompanied by locally increased strain, both effects increasing the local current. Variations are observed in both the drive current, and in the drive current enhancement normally expected from the application of strain. In addition, the effects of shallow trench isolation (STI) on MOSFET performance and on its statistical variability are investigated for the first time. The inverse-narrow-width effect of STI enhances the current density adjacent to it. This leads to a local enhancement of the influence of junction shapes adjacent to the STI. There is also a statistical impact on the threshold voltage due to random STI induced traps at the silicon/oxide interface