Niobium nitride superconducting quantum interference device (SQUID), preparation method and parameter post-processing approach

Abstract

The present invention provides a niobium nitride SQUID, a preparation method and a parameter post-processing approach. The preparation method comprises the steps of firstly depositing a niobium nitride-insulating layer-niobium nitride three-layer thin film structure on a substrate, and then preparing a superconducting ring and a bottom electrode structure of the SQUID; then preparing a plurality of parallel Josephson junctions; and then depositing an insulating thin film on the surface of the device, and holing on the surface of each Josephson junction and the surface of the bottom electrode to lead out a top electrode in the subsequent step; and then depositing a metal thin film and preparing a metal bypass resistor; and finally depositing a niobium nitride thin film and preparing a comb-shaped top electrode. By the preparation method and the parameter post-processing method of the present invention, if the numerical values of a critical current and the bypass resistor of the NbN SQUID are discovered to have larger deviation with the design values by a test, the post processing can be carried out on the device, so that the numerical values of the critical current and the bypass resistor approach the design numerical values, and the consistency of the device is improved.

Description

technical field [0001] The invention belongs to the field of superconducting quantum interference devices (SQUID), and relates to a niobium nitride superconducting quantum interference device, in particular to a niobium nitride SQUID device, a preparation method and a parameter post-processing method. Background technique [0002] The principle of superconducting quantum interference device (SQUID) is magnetic flux quantization and Josephson effect. Structurally, SQUID device is composed of superconducting Josephson junction and superconducting ring. This device can convert the small magnetic field change induced by the device into Therefore, SQUID is equivalent to a magnetic field-voltage conversion device, which is the most sensitive sensor for measuring magnetic field so far. At the temperature of liquid helium (4.2K), the magnetic flux sensitivity of low-temperature superconducting SQUID devices made of low-temperature superconducting materials (such as Nb or NbN) is usu...

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Problems solved by technology

[0005] In view of the shortcomings of the prior art described above, the object of the present invention is to provide a niobium nitride SQUID device, a preparation method and a parameter post-processing method, which are used to solve the problem of insulating layer thickness control in the niobium nitride SQUID device in the prior art Difficulties leading to low device fabrication efficiency

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