A kind of magnetic flux-driven Josephson parametric amplifier and preparation method thereof

Abstract

The invention provides a magnetic flux-driven Josephson parametric amplifier and a preparation method thereof. The preparation method includes: forming a Nb / Al-AlOx / Nb laminated structure on the surface of a substrate; etching the Nb / Al-AlOx / Nb laminated layer structure to form a coplanar waveguide resonator structure, a pump line structure, a ground line structure, a signal input wiring structure and a pump input wiring structure, and Nb / Al‑AlOx / Nb Josephson is formed in the coplanar waveguide resonator structure. junction; an insulating layer is formed on the surface of the above-mentioned structure, and the insulating layer is etched to form a Josephson junction via hole, a ground via hole, an input signal pin via hole and a pump input pin via hole; a superconducting thin film layer is formed on the surface of the above structure , etch the superconducting thin film layer to electrically connect the Josephson junction via and the ground via, and at the same time form the ground pin in the ground via, the input signal pin in the input signal pin via, and the pump input The pump input pins are formed in the pin vias.

Description

technical field [0001] The invention belongs to superconducting electronics, in particular to a magnetic flux-driven Josephson parametric amplifier and a preparation method thereof. Background technique [0002] As a new type of computing tool, quantum computer uses the superposition principle of quantum mechanics and the characteristics of quantum entanglement, and has powerful parallel computing ability. Superconducting qubits have become one of the most likely solutions to realize quantum computers due to their low loss, good scalability, and compatibility with traditional micro-nano processing technologies. In the qubit measurement experiment, in order to protect the state of the qubit, the measurement signal power is very small, and an external amplifier is required at the output end of the circuit to amplify the output signal. Commercial HEMTs (High Electron Mobility Transistors) have noise temperatures around 4K and are difficult to use for single shot read out non-d...

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Problems solved by technology

The existing preparation methods have the following disadvantages: 1) Although the Al Josephson junction prepared by double-angle evaporation has fewer process steps, it is difficult to use plasma on the substrate or the surface of the Josephson junction before evaporating the film because the suspension bridge itself is relatively fragile. Etching for cleaning; 2) Using double-layer photoresist to prepare Al Josephson junction, there will be redundant patterns ( Image 6 (shown in the dotted line box) exists, which is not conducive to the realization of the scale of integrated circuits; 3) the superconducting transition temperature of Al thin film is low (about 1K), and it needs to work at a lower temperature

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