A thermostable trilayer resist for niobium lift-off

TL;DR

This paper introduces a new thermostable trilayer resist process enabling high-quality niobium superconducting structures with critical temperatures above 7 K, suitable for advanced nanoelectronic applications.

Contribution

The authors developed a novel high-temperature, chemically stable resist process for fabricating superconducting niobium nanostructures with improved quality and potential for single electron device fabrication.

Findings

Superconducting niobium lines above 7 K critical temperature

Successful shadow evaporation of Nb-Cu hybrid structures

Resist process suitable for very small superconducting devices

Abstract

We have developped a novel lift-off process for fabrication of high quality superconducting submicron niobium structures. The process makes use of a thermostable polymer with a high transition temperature T_{g}= 235 C and an excellent chemical stability. The superconducting critical temperature of 100 nm wide niobium lines is above 7 K. An example of shadow evaporation of a Nb-Cu submicron hybrid structure is given. A potential application of this process is the fabrication of very small single electron devices using refratory metals.