Title :
High Performance Ultra-Thin Niobium Films for Superconducting Hot-Electron Devices
Author :
Jia, X.Q. ; Kang, L. ; Liu, X.Y. ; Wang, Z.H. ; Jin, B.B. ; Mi, S.B. ; Chen, Jiann-Jong ; Xu, W.W. ; Wu, P.H.
Author_Institution :
Sch. of Electron. Sci. & Eng., Nanjing Univ., Nanjing, China
Abstract :
High-quality ultrathin film is the key element of hot-electron devices. Using a doped sputtering target, high-performance niobium (Nb) ultrathin films are grown on high-resistivity silicon (Si), magnesium oxide (MgO), and sapphire substrates, optimized by grown 1-nm-thick aluminum nitride (AlN) films on the top. Superconducting transition temperature (TC) of about 7.5 K and critical current density (JC) of about 8.2 × 106 A/cm2 at 4.2 K have been obtained for the Nb film of 6.5 nm thickness on MgO substrates. The results of the films´ structural characterization by X-ray photo electronic spectroscopy, atomic force microscopy, transmission electron microscopy, and X-ray diffraction are also presented.
Keywords :
X-ray diffraction; X-ray photoelectron spectra; aluminium compounds; atomic force microscopy; critical current density (superconductivity); niobium; sputter deposition; superconducting devices; superconducting thin films; superconducting transition temperature; transmission electron microscopy; Al2O3; AlN; MgO; Nb; Si; X-ray diffraction; X-ray photoelectronic spectroscopy; aluminum nitride films; atomic force microscopy; critical current density; doped sputtering target; high-performance ultrathin niobium films; high-resistivity silicon; magnesium oxide; sapphire substrates; size 1 nm; superconducting hot-electron devices; superconducting transition temperature; transmission electron microscopy; Magnetic films; Niobium; Silicon; Sputtering; Substrates; Superconducting transition temperature; High critical current density $(J_{rm C})$; magnetron sputtering; niobium; superconducting ultra-thin film;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
DOI :
10.1109/TASC.2012.2235508
