A de-embedding technique for metallic nanowires in microwave characterization

Abstract

The application of metallic nanowires as transmission lines at microwave frequencies has attracted interest of the nanoelectronics community in recent years. The size reduction of wires down to nano-scale inevitably introduces more challenges not only in the fabrication but in the characterization techniques. The aim of this work is to build a reliable framework to characterize a single metallic nanowire in the millimeter wave range by means of a tailored-designed coplanar waveguide platform. We conduct a comprehensive analysis on the characteristic impedances and the propagation constants of nano-scale aluminum metallic wires in relation to the change of line dimension as a function of frequency from 1 to 100GHz. A method to subtract the effect of pads and contact impedance from the measurement based on an equivalent circuit model and a cascade-based de-embedding theory is employed. We propose a quasi-TEM equivalent circuit model in the analysis to predict the measured frequency-dependent transmission line parameters. A comparison between simulated and measured result will be presented.