Ultralow 1/f Noise in a Heterostructure of Superconducting Epitaxial Cobalt Disilicide Thin Film on Silicon
Journal
ACS Nano
Journal Volume
11
Journal Issue
1
Pages
516-525
Date Issued
2017
Author(s)
Chiu S.-P.; Yeh S.-S.; Chiou C.-J.; Chou Y.-C.; Lin J.-J.; Tsuei C.-C.
Abstract
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. © 2016 American Chemical Society.
Subjects
Dangling bonds; Heterojunctions; High resolution transmission electron microscopy; Quantum computers; Quantum optics; Silicides; Silicon; Silicon oxides; Transmission electron microscopy; Cobalt disilicide; Cross sectional transmission electron microscopy; Fluctuators; Interfacial dynamics; Resistance noise; Silicon-based integrated circuits; Single-crystalline; Superconducting circuit; Superconducting transition temperature
Publisher
American Chemical Society
Type
journal article