A method of fabricating a circuit element, such as a quantum computing circuit element, including obtaining a lithography mask write file that includes mask information characterizing one or more mask features, obtaining a uniformity function that is configured to modify the mask information to compensate for a non-uniform deposition process, applying the uniformity function to the lithography mask write to obtain a modified lithography mask write file, and performing lithography as directed by the modified lithography mask write file.

A method of reducing junction resistance variation for junctions in quantum information processing devices fabricated using two-step deposition processes. In one aspect, a method includes providing a dielectric substrate, forming a first resist layer on the dielectric substrate, forming a second resist layer on the first resist layer, and forming a third resist layer on the second resist layer. The first resist layer includes a first opening extending through a thickness of the first resist layer, the second resist layer includes a second opening aligned over the first opening and extending through a thickness of the second resist layer, and the third resist layer includes a third opening aligned over the second opening and extending through a thickness of the third resist layer.

Devices, systems, methods, computer-implemented methods, apparatus, and/or computer program products that can facilitate an epitaxial Josephson junction transmon device are provided. According to an embodiment, a device can comprise a substrate. The device can further comprise an epitaxial Josephson junction transmon device coupled to the substrate. According to an embodiment, a device can comprise an epitaxial Josephson junction transmon device coupled to a substrate. The device can further comprise a tuning gate coupled to the substrate and formed across the epitaxial Josephson junction transmon device. According to an embodiment, a device can comprise a first superconducting region and a second superconducting region formed on a substrate. The device can further comprise an epitaxial Josephson junction tunneling channel coupled to the first superconducting region and the second superconducting region.

A Josephson transistor, this transistor comprising a source and a drain each comprising an electric charge reservoir in electrical contact with a semiconductor layer. Each reservoir comprises a lower face and a side face both buried inside the semiconductor layer, The lower face of each reservoir extends mainly in an intermediate plane parallel to the plane of a support, this intermediate plane being located between a lower plane and an upper plane that define the semiconductor layer. The side face of each reservoir extends mainly perpendicular to the plane of the support, this side face facing the corresponding side face of the other reservoir and being separated from this corresponding side face of the other reservoir by a channel located under a gate of this transistor.

A method for producing a superconducting vanadium silicide on a silicon layer includes treating a face of the silicon layer in order to prepare it for a deposition of vanadium silicide, then depositing a vanadium silicide layer on the prepared face of the silicon layer in order to obtain a stack of a vanadium silicide layer directly deposited on the silicon layer, then an annealing the stack which increases the critical temperature of the vanadium silicide deposited. The treating includes an operation of incorporation of argon atoms in the silicon layer through the face of the silicon layer.

Techniques and methods to form smooth metal layers deposited onto selected surfaces of Josephson junction devices are provided. For example, one or more embodiments described herein can comprise depositing a layer of a first material comprising metal atom species on a selected surface of a device layer; depositing a layer of a second material on a surface of the layer of first material; and performing plasma etching on the layer of second material and the layer of first material to form an etched surface of the layer of first material that is smoother than the surface of the layer of first material, as deposited.

A method for producing a transistor includes producing on a substrate provided with a semiconductor surface layer in which an active area can be formed, a gate block arranged on the active area. Lateral protection areas are formed against lateral faces of the gate block. Source and drain regions based on a metal material-semiconductor material compound are formed on either side of the gate and in the continuation of a portion located facing the gate block. Insulating spacers are formed on either side of the gate resting on the regions based on a metal material-semiconductor material compound.

A buffer layer can be used to smooth the surface roughness of a galvanic contact layer (e.g., of niobium) in an electronic device, the buffer layer being made of a stack of at least four (e.g., six) layers of a face-centered cubic (FCC) crystal structure material, such as copper, the at least four FCC material layers alternating with at least three layers of a body-centered cubic (BCC) crystal structure material, such as niobium, wherein each of the FCC material layers and BCC material layers is between about five and about ten angstroms thick. The buffer layer can provide the smoothing while still maintaining desirable transport properties of a device in which the buffer layer is used, such as a magnetic Josephson junction, and magnetics of an overlying magnetic layer in the device, thereby permitting for improved magnetic Josephson junctions (MJJs) and thus improved superconducting memory arrays and other devices.

A method of fabricating a circuit element, such as a quantum computing circuit element, including obtaining a lithography mask write file that includes mask information characterizing one or more mask features, obtaining a uniformity function that is configured to modify the mask information to compensate for a non-uniform deposition process, applying the uniformity function to the lithography mask write to obtain a modified lithography mask write file, and performing lithography as directed by the modified lithography mask write file.

A method of producing a quantum circuit includes forming a mask on a substrate to cover a first portion of the substrate, implanting a second portion of the substrate with ions, and removing the mask, thereby providing a nanowire. The method further includes forming a first lead and a second lead, the first lead and the second lead each partially overlapping the nanowire. In operation, a portion of the nanowire between the first and second leads forms a quantum dot, thereby providing a quantum dot Josephson junction. The method further includes forming a third lead and a fourth lead, one of the third and fourth leads partially overlapping the nanowire, wherein the third lead is separated from the fourth lead by a dielectric layer, thereby providing a Dolan bridge Josephson junction. The nanowire is configured to connect the quantum dot Josephson junction and the Dolan bridge Josephson junction in series.