Adjustment of Josephson junctions by ion implantation
US4490901A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 5, 1983 |
| Grant date | Jan 1, 1985 |
| Priority date | — |
| Expiry date | May 5, 2003 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S505/922
Abstract
A method for trimming the zero voltage Josephson current of a tunnel junction including the steps of measuring the I-V characteristics of the completed junctions to quantify the change in I.sub.o necessary to meet the design requirements, placing the tested Josephson junctions on a metal block which is mounted in the sample chamber of an ion implanter structure which is pumped to 1.10.sup.-6 Torr. The junctions, kept at room temperature and oriented at a direction nearly normal to the ion beam, are implanted with magnetically analyzed ions of energies 50 keV to 2300 keV. Spatial uniformity of the ion implant beam is .+-.2% over a sample. Uniform spatial implantation over a large area sample is obtained by either sweeping of the beam across the sample, or restoring the sample through a stationary beam, determining the required ion dose to effect trimming from calibration curves, remeasuring the I-V characteristics after implantation to confirm that the required I.sub.o trim was effected, and then completing the fabrication of the Josephson device according to standard processing.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.