Suspended metal mask techniques in Josephson junction fabrication
We report here two processes for in-situ, self-aligned fabrication of niobium based Josephson tunnel junctions and SNS microbridges in which multiple evaporations at varying angles are made through a suspended metal stencil fabricated by electron beam lithography (EBL). Both techniques have proved superior to earlier all-polymer suspended masks, particularly with e-gun evaporated refractory metals such as niobium. The first process uses a trilevel resist and ion milling to pattern a gold stencil suspended on PMMA. In the second process, an aluminum stencil suspended on polyimide (PI) is patterned by lift-off with an EBL mask written in a PMMA layer on top of the PI. The PI is then undercut using an oxygen plasma etch through the aluminum mask. Reproducible ( +- 20 nm) submicrometer dimensions and good junction characteristics have been achieved using these techniques without the need for difficult-to-control surface cleaning procedures.
- Research Organization:
- Department of Physics, State University of New York at Stony Brook, Stony Brook, New York 11794
- OSTI ID:
- 5993177
- Journal Information:
- J. Vac. Sci. Technol., B; (United States), Vol. 3:1
- Country of Publication:
- United States
- Language:
- English
Similar Records
High-performance DC SQUIDs with submicrometer niobium Josephson junctions
Stable performance Nb variable thickness microbridge type Josephson junctions: A reproducible fabrication technique
Related Subjects
GENERAL PHYSICS
JOSEPHSON JUNCTIONS
FABRICATION
MASKING
ALUMINIUM
ELECTRON BEAMS
ION COLLISIONS
NIOBIUM ALLOYS
PMMA
SURFACE CLEANING
TUNNEL EFFECT
VACUUM EVAPORATION
ALLOYS
BEAMS
CLEANING
COLLISIONS
ELEMENTS
ESTERS
EVAPORATION
JUNCTIONS
LEPTON BEAMS
METALS
ORGANIC COMPOUNDS
ORGANIC POLYMERS
PARTICLE BEAMS
PHASE TRANSFORMATIONS
POLYACRYLATES
POLYMERS
POLYVINYLS
SUPERCONDUCTING JUNCTIONS
SURFACE FINISHING
420201* - Engineering- Cryogenic Equipment & Devices