Self-aligned thin film structures with 1000 Å resolution

A two-level e-beam resist process is described which is capable of producing features under 1000 Å in size. The process is compatible with oblique evaporation technique so that high-accuracy alignment can be obtained in multiple-layer device structures. Tunnel junction structures with areas as small as 10−10 cm2 have been fabricated. The estimated capacitance for such junctions is <10−15 F. Such structures have application in low-capacitance Josephson logic circuits. The process is also applicable to fabrication of submicron MOM diodes and other devices which can be made using a lift-off technique.