Investigation of the superconducting properties of NbN films deposited by DC magnetron sputtering on a high-k dielectric HfO₂ buffer layer

Abstract

The influence of the buffer layer of hafnia dielectric (HfO 2 ) on superconducting properties of niobium nitride films (NbN), produced by the technique of the reactive magnetron depositing has been investigated for the first time. This study presents a comprehensive analysis of morphological, microstructural, and electrophysical parameters of thin NbN films. The dependence of transition critical temperature from the thickness of the HfO 2 buffer layer has been obtained. For the first time, it has been demonstrated that the superconducting properties of niobium nitride films at the HfO 2 buffer layer have high superconductive parameters, namely, Т c ~ 13 K (at the film thickness of approximately 30 nm) and high critical current density of approximately 10 7 A/cm 2 . The relation between the thickness of the HfO 2 buffer layer with the critical current density of niobium nitride films has been determined. It appeared that the values of critical current density increase significantly up to 13 MA/cm 2 when the thickness of the hafnia buffer layer is more than 2 nm.

Niobium Nitride Preparation for Superconducting Single-Photon Detectors

“…Magnetron sputtering is a physical vapor deposition (PVD) technique, and it is reportedly the most widely used method for preparing NbN thin films [6,[18][19][20]. In the mature magnetron sputtering deposition process, it has been found that various process conditions, such as the substrate material, the substrate temperature, the nitrogen partial pressure (nitrogen content), the radio frequency bias, and the deposition thickness, can affect the structure and superconducting properties of the films.…”

Study of morphological, physical and mechanical properties of thin NbN films synthesized via DC magnetron sputtering system

“…Also, it found that the work under the NbN superconducting critical temperature T c with range of 40 to 5 K depending on thickness of the film as well as its quality and substrate of suitable (growth of epitaxial as well as crystal of single) (Slysz et al , 2011). In addition, properties of a superconductor were studied for NbN thin films prepared via magnetron sputtering (DC) using high-k dielectric HfO 2 like buffer layer (Porokhov et al , 2021; Chockalingam et al , 2008) using MgO (100) substrate that it has crystalline of single below many conditions using magnetron sputtering (influence of power and ratio of nitrogen gas).…”