Ultralow 1/f Noise in a Heterostructure of Superconducting Epitaxial Cobalt Disilicide Thin Film on Silicon

Shao Pin Chiu, Sheng-Shiuan Yeh, Chien Jyun Chiou, Yi-Chia Chou*, Juhn-Jong Lin, Chang Chyi Tsuei

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

17 Scopus citations


High-precision resistance noise measurements indicate that the epitaxial CoSi2/Si heterostructures at 150 and 2 K (slightly above its superconducting transition temperature Tc of 1.54 K) exhibit an unusually low 1/f noise level in the frequency range of 0.008-0.2 Hz. This corresponds to an upper limit of Hooge constant γ ≤ 3 × 10-6, about 100 times lower than that of single-crystalline aluminum films on SiO2 capped Si substrates. Supported by high-resolution cross-sectional transmission electron microscopy studies, our analysis reveals that the 1/f noise is dominated by excess interfacial Si atoms and their dimer reconstruction induced fluctuators. Unbonded orbitals (i.e., dangling bonds) on excess Si atoms are intrinsically rare at the epitaxial CoSi2/Si(100) interface, giving limited trapping-detrapping centers for localized charges. With its excellent normal-state properties, CoSi2 has been used in silicon-based integrated circuits for decades. The intrinsically low noise properties discovered in this work could be utilized for developing quiet qubits and scalable superconducting circuits for future quantum computing.

Original languageEnglish
Pages (from-to)516-525
Number of pages10
JournalACS Nano
Issue number1
StatePublished - 24 Jan 2017


  • 1/f resistance noise
  • dimer reconstruction
  • interfacial dynamic defects
  • superconducting silicide/silicon heterostructure
  • two-level-system fluctuators


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