Large area arrays of metal nanowires

Abstract

We present novel modified lift-off processes for the fabrication of large-area, uniform metal nanowire arrays. In all processes, dense line arrays with periods in the 50–100 nm range were obtained in photoresist films with Extreme Ultraviolet Interference Lithography (EUV-IL). The critical problem of preparing lift-off masks with a negative resist profile is solved by the use of either a bilayer resist stack of HSQ/PMMA or deposition of a metal layer at oblique angles on top of the patterned resist lines. As an added benefit, the metal deposition step enables fine-tuning of the width of the nanowires. Using the developed processes, Au and Cr nanowires with 8 nm–70 nm linewidth were obtained.