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

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 & 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 (T-a) and the film thickness. The superconducting critical temperature (T-c) strongly depends on T-a and the maximum T-c obtained from the demonstrated technique is about 4.8 K for the thickness range similar to 12 nm and above. Besides, the dynamics of IVCs get modulated by the appearance of intermediated resistive steps for decreased T-a and the steps get more prominent for reduced thickness. Further, the deviation in the temperature dependent critical current (I-c) from the Ginzburg-Landau theoretical limit varies strongly with the thickness. Finally, the T-c, intermediate resistive steps in the IVCs and the depairing current are observed to alter in a similar fashion with T-a and the thickness indicating the robustness of the synthesis process to fabricate disordered nitride-based superconductor.

Automated summary

Disorder induced phase slip events were observed in current voltage characteristics of two-dimensional TiN thin films produced through robust substrate mediated nitridation technique. The critical temperature and resistive steps in the characteristics were found to vary strongly with annealing temperature and thickness, indicating the robustness of the synthesis process in fabricating disordered nitride-based superconductor.