A silicon-based niobium nitride thin film superconducting material and its manufacturing method

Abstract

The invention prepares a silicon-based niobium nitride thin film superconducting material, which includes a Si base, a TiN transition layer, and an NbN layer. Due to the large lattice mismatch in growing NbN films directly on Si substrates, a certain thickness of non-superconducting interface distortion layer will exist in the NbN films, seriously reducing the superconducting properties of NbN. TiN and NbN both have a face-centered cubic structure, and the lattice mismatch is small. Therefore, using the TiN transition layer greatly reduces the thickness of the interface distortion layer in the NbN film, and at the same time, the crystallinity of NbN is improved, thereby improving its superconductivity. performance; and NbTiN itself is a superconducting material with a high Tc. Even if the two elements Ti and N in TiN enter the NbN film, it will not decrease, but will improve its superconducting performance. At the same time, the invention also proposes a method for producing the silicon-based niobium nitride thin film superconducting material.

Description

technical field [0001] The invention relates to the field of superconducting material production, in particular to a silicon-based niobium nitride thin film superconducting material and a production method thereof. Background technique [0002] NbN (niobium nitride) thin film is the core material of various superconducting devices, such as superconducting tunnel junction (Superconducting tunnel junction), hot electron bolometer (HEB, Hot Electron Bolometer), superconducting single photon detection device (SSPD, SuperconductingSinglePhotonDetector), etc. . Usually, NbN thin films are prepared on MgO single crystal substrates by vacuum magnetron sputtering technology. The main consideration is that the lattice mismatch between NbN and MgO is small (~4%), and the grown NbN thin films have good superconducting properties. . However, the price of MgO single crystal substrate is high, the micro-nano processing technology of subsequent devices is immature, and the loss of devices...

AI Technical Summary

Problems solved by technology

However, these materials have two major disadvantages: one is that the crystal structure and lattice mismatch are still relatively large; the other is that the constituent elements of these materials will reduce the superconducting properties of NbN films if they diffuse into the NbN film

Therefore, there is still a gap between the existing Si-based NbN ultra-thin films and the superconducting properties of MgO-based NbN ultra-thin films. Exploring better transition layer materials to prepare Si-based NbN films can improve their superconducting properties. The material design and application range of superconducting thin films are very meaningful

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