An Efficient 5-Input Exclusive-OR Circuit Based on Carbon Nanotube FETs

Abstract

An Efficient 5-Input Exclusive-OR Circuit Based on Carbon Nanotube FETs Ronak Zarhoun, Mohammad Hossein Moaiyeri, Samira Shirinabadi Farahani, and Keivan Navi The integration of digital circuits has a tight relation with the scaling down of silicon technology. The continuous scaling down of the feature size of CMOS devices enters the nanoscale, which results in such destructive effects as short channel effects. Consequently, efforts to replace silicon technology with efficient substitutes have been made. The carbon nanotube field- effect transistor (CNTFET) is one of the most promising replacements for this purpose because of its essential characteristics. Various digital CNTFET-based circuits, such as standard logic cells, have been designed and the results demonstrate improvements in the delay and energy consumption of these circuits. In this paper, a new CNTFET-based 5-input XOR gate based on a novel design method is proposed and simulated using the HSPICE tool based on the compact SPICE model for the CNTFET at the 32-nm technology node. The proposed method leads to improvements in performance and device count compared to the conventional CMOS-style design. Keywords: Nanotechnology, carbon nanotube field- effect transistor, CNTFET, high-performance circuits, CNTFET-based inverter, exclusive-OR gate, XOR gate. Manuscript received Jan. 13, 2013; revised Apr. 2, 2013; accepted Apr. 5, 2013. Ronak Zarhoun (phone: +98 2129904195, r.zarhoon@mail.sbu.ac.ir), Mohammad H. Moaiyeri (h_moaiyeri@sbu.ac.ir), and Samira S. Farahani (sa.shirinabadi@mail.sbu.ac.ir) are with the Nanotechnology and Quantum Computing Laboratory, Shahid Beheshti University, G.C., Tehran, Iran. Keivan Navi (corresponding author, navi@sbu.ac.ir, knavi@uci.edu) is with the Quantum Computing Laboratory, Shahid Beheshti University, G.C., Tehran, Iran, and is also with the Department of Electrical Engineering and Computer Science, University of California, Irvine, Irvine, CA, USA. ETRI Journal, Volume 36, Number 1, February 2014 http://dx.doi.org/10.4218/etrij.14.0113.0051 I. Introduction No one can imagine today’s world without the influence and power of computer technology, which dominates many aspects of people’s lives, from such simple details as cell phones to such important and critical projects as those in aeronautics. All computer-based technological improvements are possible through computational functions, which are made up of precise logic gates. Such logic gates as NOT, NAND, NOR, and XOR are the main building blocks of logical functions [1], [2]. Considering these gates, the XOR gate plays a significant role in computational processors with low-power purposes and arithmetic circuits [3], [4], such as full adder cells [5], [6]-[8], parity bit generators and parity checkers [9], multipliers such as the polynomial basis multiplier [10], and comparator circuits [8], [11], [12]. High-speed XOR gates are needed for summation of partial products in multiplier circuits, and they are also used in MUX modules in arithmetic circuits [12]. The most famous application of the XOR gate is in coding processes and data encryption or decryption, especially in AES (Advanced Encryption Standard) [1], which is sufficiently used in data communication. In design testing, it is used in built-in self-test structures [10] and is essential in cryptography [9], FPGAs, and high-performance structures. The XOR gate is even used in compressors, phase detectors, error detection, and error correction circuits [13]. Digital signal processor circuits with a logarithmic number system composed of several multipliers and adders benefits from XOR gates [14]. Moreover, the important role of this gate has even appeared in optical telecommunication networks for bit pattern recognition, operations related to address comparison, and so on [15], [16]. Design and development of XOR gates with conventional CMOS architecture is limited by the number of its inputs. As a Ronak Zarhoun et al.