A Robust nitridation technique for fabrication of disordered superconducting TiN thin films featuring phase slip events

TL;DR

This paper presents a robust nitridation method to fabricate disordered TiN thin films that exhibit phase slip events, with superconducting properties tunable by annealing temperature and film thickness, relevant for superconducting device applications.

Contribution

The study introduces a substrate-mediated nitridation technique that controllably induces disorder in TiN films, enabling phase slip phenomena and tunable superconducting properties.

Findings

Maximum Tc of about 4.8 K achieved for ~12 nm thick films.

Intermediate resistive steps observed in IVCs depend on annealing temperature and thickness.

Depairing current and Tc vary similarly with synthesis parameters.

Abstract

Disorder induced phase slip (PS) events appearing in the current voltage characteristics (IVCs) are reported for two-dimensional TiN thin films produced by a robust substrate mediated nitridation technique. Here, high temperature annealing of Ti/Si3N4 based metal/substrate assembly is the key to produce majority phase TiN accompanied by TiSi2 and elemental Si as minority phases. The method itself introduces different level of disorder intrinsically by tuning the amount of the non-superconducting minority phases that are controlled by annealing temperature (Ta) and the film thickness. The superconducting critical temperature (Tc) strongly depends on Ta and the maximum Tc obtained from the demonstrated technique is about 4.8 K for the thickness range of about 12 nm and above. Besides, the dynamics of IVCs get modulated by the appearance of intermediated resistive steps for decreased Ta and the steps get more prominent for reduced thickness. Further, the deviation in the temperature dependent critical current (Ic) from the Ginzburg-Landau theoretical limit varies strongly with the thickness. Finally, the Tc, intermediate resistive steps in the IVCs and the depairing current are observed to alter in a similar fashion with Ta and the thickness indicating the robustness of the synthesis process to fabricate disordered nitride-based superconductor.