A physical vapor deposition system includes a chamber, three target supports to targets, a movable shield positioned having an opening therethrough, a workpiece support to hold a workpiece in the chamber, a gas supply to deliver nitrogen gas and an inert gas to the chamber, a power source, and a controller. The controller is configured to move the shield to position the opening adjacent each target in turn, and at each target cause the power source to apply power sufficient to ignite a plasma in the chamber to cause deposition of a buffer layer, a device layer of a first material that is a metal nitride suitable for use as a superconductor at temperatures above 8° K on the buffer layer, and a capping layer, respectively.

According to various implementations of the invention, a vertical Josephson Junction device may be realized using molecular beam epitaxy (MBE) growth of YBCO and PBCO epitaxial layers in an a-axis crystal orientation. Various implementations of the invention provide improved vertical JJ devices using SiC or LSGO substrates; GaN, AlN, or MgO buffer layers; YBCO or LSGO template layers; YBCO conductive layers and various combinations of barrier layers that include PBCO, NBCO, and DBCO. Such JJ devices are simple to fabricate with wet and dry etching, and allow for superior current flow across the barrier layers.

This disclosure relates to fabrication of step edges to fabricate Josephson junctions. A method comprises forming a layer of resist over the surface. The layer of resist comprises openings to expose a selected area of the surface, thereby forming two walls in the layer of resist on a perimeter of the selected area. The resist and the substrate are exposed to an ion beam, thereby etching the resist and the exposed areas of the surface. While exposing the resist and the substrate to the ion beam, the substrate is gradually rotated about an axis normal to the surface to thereby form two step edges at the respective two walls. Further, superconducting material is deposited onto the substrate in a meandering shape to form a path that crosses the two step edges multiple times and to form a Josephson junction each time the path crosses the step edges.

Nano-scale junctions, wires, and junction arrays are created by using a focused high-energy ion beam to direct-write insulating or poorly conducting barriers into thin films of materials that are sensitive to disorder, including superconductors, ferromagnetic materials and semiconductors.

This disclosure relates to fabrication of step edges to fabricate Josephson junctions. A method comprises forming a layer of resist over the surface. The layer of resist comprises openings to expose a selected area of the surface, thereby forming two walls in the layer of resist on a perimeter of the selected area. The resist and the substrate are exposed to an ion beam, thereby etching the resist and the exposed areas of the surface. While exposing the resist and the substrate to the ion beam, the substrate is gradually rotated about an axis normal to the surface to thereby form two step edges at the respective two walls. Further, superconducting material is deposited onto the substrate in a meandering shape to form a path that crosses the two step edges multiple times and to form a Josephson junction each time the path crosses the step edges.

Solid-state devices including a layer of a superconductor material epitaxially grown on a crystalline high thermal conductivity substrate, the superconductor material being one of TiNx, ZrNx, HfNx, VNx, NbNx, TaNx, MoNx, WNx, or alloys thereof, and one or more layers of a semiconducting or insulating or metallic material epitaxially grown on the layer of superconductor material, the semiconducting or insulating material being one of a Group III N material or alloys thereof or a Group 4b N material or SiC or ScN or alloys thereof.

A method for measuring conductance of a material real-time during etching/milling includes providing a fixture having a socket for receiving the material. The socket is attached to a printed circuit board (PCB) mounted on one side of a plate that has at least one opening for providing ion beam access to the material sample. Conductive probes extend from the other side of the PCB to contact and span a target area of the material. A measurement circuit in electrical communication with the probes measures the voltage produced when a current is applied across the material sample to measure changes in electrical properties of the sample over time.

A device is disclosed that includes a substrate, a first superconducting quantum interference device (SQUID), a second SQUID and a third SQUID. The first SQUID is disposed on the substrate and has a first feature dimension, a second feature dimension and a first effective geometric magnetic inductance parameter value, .sub.L1. The second SQUID is disposed on the substrate and has the first feature dimension, a third feature dimension and a second effective geometric magnetic inductance parameter value, .sub.L2. The third SQUID is disposed on the substrate and has the first feature dimension, a fourth feature dimension and a third effective geometric magnetic inductance parameter value, .sub.L3, wherein .sub.L1<.sub.L2<.sub.L3.

A physical vapor deposition system includes a chamber, three target supports to targets, a movable shield positioned having an opening therethrough, a workpiece support to hold a workpiece in the chamber, a gas supply to deliver nitrogen gas and an inert gas to the chamber, a power source, and a controller. The controller is configured to move the shield to position the opening adjacent each target in turn, and at each target cause the power source to apply power sufficient to ignite a plasma in the chamber to cause deposition of a buffer layer, a device layer of a first material that is a metal nitride suitable for use as a superconductor at temperatures above 8 K on the buffer layer, and a capping layer, respectively.

According to various implementations of the invention, a vertical Josephson Junction device may be realized using molecular beam epitaxy (MBE) growth of YBCO and PBCO epitaxial layers in an a-axis crystal orientation. Various implementations of the invention provide improved vertical JJ devices using SiC or LSGO substrates; GaN, AlN, or MgO buffer layers; YBCO or LSGO template layers; YBCO conductive layers and various combinations of barrier layers that include PBCO, NBCO, and DBCO. Such JJ devices are simple to fabricate with wet and dry etching, and allow for superior current flow across the barrier layers.