title: Ultralow 1/f Noise in a Heterostructure of Superconducting Epitaxial Cobalt Disilicide Thin Film on Silicon.
abstract: High-precision resistance noise measurements indicate that the epitaxial CoSi2/Si heterostructures at 150 and 2 K (slightly above its superconducting transition temperature Tcof 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 SiO2capped 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, CoSi2has 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.
authors.forename: Shao-Pin
authors.identifier: 0000-0001-7603-5822
authors.initials: SP
authors.lastname: Chiu
authors.forename: Sheng-Shiuan
authors.initials: SS
authors.lastname: Yeh
authors.forename: Chien-Jyun
authors.initials: CJ
authors.lastname: Chiou
authors.forename: Yi-Chia
authors.initials: YC
authors.lastname: Chou
authors.forename: Juhn-Jong
authors.identifier: 0000-0001-8640-3617
authors.initials: JJ
authors.lastname: Lin
authors.affiliation: IBM Thomas J. Watson Research Center , Yorktown Heights, New York 10598, United States.
authors.forename: Chang-Chyi
authors.initials: CC
authors.lastname: Tsuei
keywords: 1/f resistance noise; dimer reconstruction; interfacial dynamic defects; superconducting silicide/silicon heterostructure; two-level-system fluctuators