DocumentCode :
1764589
Title :
Normal-Metal–Insulator–Superconductor Tunnel Junction With Atomic-Layer-Deposited Titanium Nitride as Superconductor
Author :
Torgovkin, Andrii ; Chaudhuri, Saumyadip ; Malm, Jari ; Sajavaara, Timo ; Maasilta, Ilari J.
Author_Institution :
Dept. of Phys., Univ. of Jyvaskyla, Jyvaskyla, Finland
Volume :
25
Issue :
3
fYear :
2015
fDate :
42156
Firstpage :
1
Lastpage :
4
Abstract :
We report the fabrication of 70–350-nm-thick superconducting titanium nitride (TiNx) films using the atomic layer deposition (ALD) technique and the subsequent fabrication of normal metal–insulator–superconductor (NIS) tunnel junction devices from the ALD films. The films were deposited on a variety of substrates: silicon, silicon nitride, sapphire, and magnesium oxide. Superconductivity, with transition temperatures 
ranging from 1.35 to 1.89 K, was observed in all films. 
was found to depend on both the substrate type as well as film thickness. Cu-TiOx -TiNx NIS tunnel junction devices were fabricated from the TiN film deposited on silicon, using electron beam lithography and shadow angle evaporation techniques. These devices exhibit temperature-dependent current–voltage characteristics and good thermometric response from 0.1 K to slightly above . Nonlinearity in the current–voltage characteristics was observed even at temperatures as high as 5 , indicating the presence of a pseudogap in these TiNx films.
Keywords :
atomic layer deposition; copper; electrical conductivity; electron beam lithography; superconducting junction devices; superconducting materials; superconducting thin films; superconducting transition temperature; superconductive tunnelling; thin film devices; titanium compounds; vacuum deposition; ALD films; Al2O3; Cu-TiOx-TiNx; MgO; Si; SiN; atomic-layer-deposited titanium nitride; electron beam lithography; film thickness; magnesium oxide substrates; normal-metal-insulator-superconductor tunnel junction devices; pseudogap; sapphire substrates; shadow angle evaporation techniques; silicon nitride substrates; silicon substrates; size 70 nm to 350 nm; superconducting titanium nitride films; superconducting transition temperature; temperature-dependent current-voltage characteristics; thermometric response; Films; Junctions; Substrates; Superconducting films; Superconducting transition temperature; Temperature; Temperature measurement; Atomic layer deposition; pseudogap; superconductivity; thermometry; thin film; tunnel junctions;
fLanguage :
English
Journal_Title :
Applied Superconductivity, IEEE Transactions on
Publisher :
ieee
ISSN :
1051-8223
Type :
jour
DOI :
10.1109/TASC.2014.2383914
Filename :
6991555
Link To Document :
