Fabrication techniques for nanometer scale resistors: A poor man’s nanolithography

A variety of techniques were developed to enable the fabrication of submicron resistors suitable for conductance and noise measurements. Small wires with effective diameters of 400 Å and lengths of 750–2000 Å were fabricated by these means. The techniques are suitable for the fabrication of wires with lengths down to less than 500 Å and effective diameters down to less than 150 Å, and require only standard photolithography and thin film deposition equipment. The processing schemes are an offshoot of those previously developed by Prober et al. [Appl. Phys. Lett. 37, 94 (1980)] for the fabrication of long (>1 μm) small-diameter wires. The techniques reported here include an improved method for making long wires, an alternative method for materials that cannot be handled by that approach, and new techniques to enable the fabrication of wires with lengths well below the 1 μm limit of standard photolithography.