A Nanoscale-Localized Ion Damage Josephson Junction Using Focused Ion Beam and Ion Implanter.
High-T(c) Josephson junctions were fabricated by nanolithography using focused ion beam (FIB) milling and ion implantation. The junctions were formed in a YBa2Cu3O7-x, thin film in regions defined using a gold-film mask with 50-nm-wide (top) slits, engraved by FIB. The focused ion beam system parameters for dwell time and passes were set to remove gold up to a precise depth. 150 keV oxygen ions were implanted at a nominal dose of up to 5 x 10(13) ions/cm2 into YBa2Cu3O7-x microbridges through the nanoscale slits. The current-voltage curves of the ion implantation junctions exhibit resistive-shunted-junction-like behavior at 77 K. The junction had an approximately linear temperature dependence of critical current. Shapiro steps were observed under microwave irradiation. A 50-nm-wide slit and 0-20-nm-thick buffer layers were chosen in order to make Josephson junctions due to the V-shape of the FIB-milled trench.
C H
CH
Wu
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Ku
F J
FJ
Jhan
J H
JH
Chen
J T
JT
Jeng
D004563:Electrochemistry; D006046:Gold / Q000737:chemistry; D007477:Ions / Q000737:chemistry*; D008670:Metals / Q000737:chemistry; D008855:Microscopy, Electron, Scanning; D049329:Nanostructures / Q000737:chemistry*; D036103:Nanotechnology / Q000379:methods*; D010100:Oxygen / Q000737:chemistry
D007477:Ions; D008670:Metals; D006046:Gold; D010100:Oxygen