Fabrication and characterization of an attonewton-sensitivity Si cantilever with an Nb micro-ring

Autor: Jae-Hyuk Choi, Yun Won Kim, Heon Hwa Choi, Soon-Gul Lee
Rok vydání: 2012
Předmět:
Zdroj: Journal of the Korean Physical Society. 60:973-977
ISSN: 1976-8524
0374-4884
DOI: 10.3938/jkps.60.973
Popis: We have fabricated ultrasensitive silicon cantilevers integrated with a superconducting Nb microring as a key part of a flux quantum-based force measurement system and have characterized both their mechanical and superconducting properties by using mechanical methods. A 50-nm-thick Nb ring with inner and outer radii of 5 µm and 10 µm was mounted by DC magnetron sputtering and lift-off on the end of a 410-µm-long, 4-µm-wide and 340-nm-thick single-crystalline silicon cantilever. The cantilever showed a force sensitivity as good as \({{4.2 aN} \mathord{\left/ {\vphantom {{4.2 aN} {\sqrt {Hz} }}} \right. \kern-\nulldelimiterspace} {\sqrt {Hz} }}\) at 3 K, which was estimated from its spring constant of 2.6 × 10−5 N/m and a quality factor of 31000. The superconducting property of the Nb micro-ring was observed from the variation of the cantilever’s vibration amplitude while the vibration was driven by an excitation coil, showing a transition temperature of 7 K. The superconducting transition was also confirmed through an electrical transport measurement for a separately-prepared Nb strip film on a silicon wafer.
Databáze: OpenAIRE
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