Thermostable trilayer resist for niobium lift-off

We have developed a novel lift-off process for fabrication of high quality superconducting submicron niobium structures. The process makes use of a th ermostable polymer with a high transition temperature T-g = 235 degrees C a nd an excellent chemical stability. The superconducting critical temperatur e of 150-nm-wide niobium lines is above 7 K. An example of shadow evaporati on of a Nb-Cu submicron hybrid structure is given. A potential application of this process is the fabrication of very small single electron devices us ing refractory metals. (C) 2000 American Vacuum Society.