Disorder control ofT_Cin thin film Mo

Abstract

We have looked at the dependence of the superconducting transition temperature on the deposition parameters of magnetron sputtered Mo on Si 3 N 4 coated Si substrates. From the measurements we can conclude that impurity inclusion/disorder and strain have an influence on the transition temperature, where under certain conditions a transition temperature as high as 2.4 K could be reached. This is significantly above the 900 mK measured for bulk Mo. The impurity content and strain in the film are influenced by the deposition rate, substrate bias, working gas pressure, substrate structure and system pre-conditioning. A model based on the change of the Coulomb interaction potential due to defect/disorder generation, without a significant change in the density of states, was shown to best explain the results observed.

Studies on DC transport and terahertz conductivity of granular molybdenum thin films for microwave radiation detector applications

“…While the Mo-A film becomes superconducting at 4.17 K, the global TC for the Mo-B film is at 3.23 K. The increase in the TC of the films may be ascribed either to the surface phonon softening due to increased surface to volume ratio, thereby increasing the electron-phonon coupling strength 38 or to the increased spectral density around the Fermi surface due to fluctuations in the discrete energy levels of the nanocrystalline grains 39,40 . Similar enhancements in the TC have already been reported earlier 14,41 . The log-log plot in figure 4 , where 0 is the superconducting gap at zero temperature 9 .…”

Degradation in molybdenum thin films and Mo/AuPd bilayers and its reduction by sidewall passivation

“…However, MoO 2 (66 at.%) would also fit the error margins. Unoxidized samples left in ambient conditions for one week showed no significant changes in comparison to the reference samples stored in a desiccator, confirming the findings in [13]. Furthermore, partly oxidized samples showed similar stability.…”

Characterizing the stress and electrical properties of superconducting molybdenum films

“…Molybdenum (Mo) films, due to its low resistivity and remarkable chemical stability, have been widely used in transitionedge sensor (TES) devices [1][2][3][4][5][6][7][8][9]. Traditionally served as the superconducting layer in the proximity bilayer strategy for fabricating TES devices, Mo film has been characterized in terms of stress, morphology, resistivity and superconductivity [5,[10][11][12][13], from which lessons have been learned as how to improve the performance of the films with state-of-the-art deposition technologies. * Authors to whom any correspondence should be addressed.…”

“…In practice, it is quite difficult to control the T c of Mo films accurately, because of its high sensitivity to film deposition parameters. The relationships between the T c and other properties of Mo film, as reported by different research groups involved in TES development, are often confusing and sometimes inconsistent with each other [4,12,14,15]. It is clear that the underlying physics determining T c variation is still not understood, and thus more relevant data are needed to gain further insight into the origin of T c variation.…”