A digital circuit includes at least one quantum wire resonant tunneling transistor that includes an emitter terminal, a base terminal, a collector terminal, an emitter region in connection with the emitter terminal, a base region in connection with the base terminal, a collector region in connection with the collector terminal, an emitter barrier region between the emitter region and the base region, and a collector barrier region between the collector region and the base region. At least one of the emitter region, the base region, and the collector region includes a plurality of metal quantum wires.

The invention includes methods, and the structures formed, for multi-qubit chips. The methods may include annealing a Josephson junction of a qubit to either increase or decrease the frequency of the qubit. The conditions of the anneal may be based on historical conditions, and may be chosen to tune each qubit to a desired frequency.

Techniques regarding selectively tuning the operating frequency of superconducting Josephson junction resonators are provided. For example, one or more embodiments described herein can comprise a method that can include chemically altering a Josephson junction of a Josephson junction resonator via a plasma treatment. The method can also comprise selectively tuning an operating frequency of the Josephson junction resonator based on a property of the plasma treatment.

Systems and techniques providing suitable chip structures for facilitating antenna-based thermal annealing of qubits are provided. In one example, a radio frequency emitter can comprise a voltage-controlled oscillator and an antenna. The voltage-controlled oscillator can receive power-on signals from a microcontroller, thereby causing the voltage-controlled oscillator to generate an electromagnetic wave. The antenna can then direct the electromagnetic wave onto a set of one or more capacitor pads of a Josephson junction on a superconducting qubit chip, thereby annealing the Josephson junction. In another example, a voltage regulator and a digital-to-analog converter or digital-to-digital converter can be coupled in series between the microcontroller and the voltage-controlled oscillator, thereby allowing the voltage-controlled oscillator to be voltage and/or frequency tunable and eliminating the need for external power routing as compared to photonic laser annealing. In yet another example, a bipolar-junction and complementary metal-oxide semiconductor stack construction can be employed.

An embodiment includes a method and device for forming a multi-qubit chip. The method includes forming a plurality of qubits on a chip, where each qubit comprises a Josephson junction. The method includes annealing one or more Josephson junctions. Annealing is performed by one or more of a plurality of laser emission sources on a planar lightwave circuit. Each of the laser emission sources is located above each qubit.

Systems and techniques facilitating antenna-based thermal annealing of qubits are provided. In one example, a radio frequency emitter, transmitter, and/or antenna can be positioned above a superconducting qubit chip having a Josephson junction coupled to a set of one or more capacitor pads. The radio frequency emitter, transmitter, and/or antenna can emit an electromagnetic signal onto the set of one or more capacitor pads. The capacitor pads can function as receiving antennas and therefore receive the electromagnetic signal. Upon receipt of the electromagnetic signal, an alternating current and/or voltage can be induced in the capacitor pads, which current and/or voltage thereby heat the pads and the Josephson junction. The heating of the Josephson junction can change its physical properties, thereby annealing the Josephson junction. In another example, the emitter can direct the electromagnetic signal to avoid unwanted annealing of neighboring qubits on the superconducting qubit chip.

A mixed semiconductor-superconductor platform is fabricated in phases. In a masking phase, a dielectric mask is formed on a substrate, such that the dielectric mask leaves one or more regions of the substrate exposed. In a selective area growth phase, a semiconductor material is selectively grown on the substrate in the one or more exposed regions. In a superconductor growth phase, a layer of superconducting material is formed, at least part of which is in direct contact with the selectively grown semiconductor material. The mixed semiconductor-superconductor platform comprises the selectively grown semiconductor material and the superconducting material in direct contact with the selectively grown semiconductor material.

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.

An embodiment includes a method and device for forming a multi-qubit chip. The method includes forming a plurality of qubits on a chip, where each qubit comprises a Josephson junction. The method includes annealing one or more Josephson junctions. Annealing is performed by one or more of a plurality of laser emission sources on a planar lightwave circuit. Each of the laser emission sources is located above each qubit.

Disclosed is a charged particle beam system comprising a charged particle beam column having a charged particle source forming a charged particle beam, an objective lens and a first deflection system for changing a position of impingement of the charged particle beam in a sample plane. The system further comprises a sample chamber comprising a sample stage for holding a sample to be processed, and a controller configured to create and store a height map of a sample surface. The controller is further configured to dynamically adjust the objective lens of the charged particle beam in dependence on a position of impingement of the charged particle beam according to the height map.