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Proceedings Paper

Single-crystal silicon triple-torsional micro-oscillators for use in magnetic resonance force microscopy
Author(s): Michelle Diane Chabot; Troy C. Messina; Vladimir Mancevski; Casey W. Miller; John T. Markert
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Paper Abstract

Single-crystal silicon triple-torsional micro-oscillators have been fabricated, characterized, and modeled primarily for use in a magnetic resonance force microscope. These structures exploit a high-Q triple-torsional mode of oscillation while providing added stability. Fabrication involves lithography, reactive ion etch, and a final KOH wet-etch, with the final oscillator material being single-crystal boron-doped silicon. Typical oscillators were 250 nm thick and 10 - 200 microns in lateral dimensions. Finite element modeling provided the sequence and structure of the ten lowest-frequency modes and indicated that the upper torsional mode best isolates the motion from losses to the base. The oscillators were excited piezoelectrically and the resulting frequency-dependent motion was detected with fiber-optic interferometry, with a 0.002 nm/Hz1/2 resolution. Phase-sensitive motion detection at various points on the oscillator facilitated the assignment of the principle modes. Magnetic excitation was also investigated in order to best excite the torsional resonances. Cobalt micromagnets with moments below 10-12 J/T were electron-beam deposited onto oscillators, and the magnetic forces were measured. MRFM, the primary intended application of these novel structures, is discussed; in particular, an overview is given of an experiment which uses a double-torsional micro-oscillator for the force detection of nuclear magnetic resonance. All topics discussed in this work are being combined in order to achieve a NMRFM single-sweep sensitivity as low as 10-16 N/Hz1/2 at room temperature.

Paper Details

Date Published: 1 October 2001
PDF: 12 pages
Proc. SPIE 4559, MEMS Components and Applications for Industry, Automobiles, Aerospace, and Communication, (1 October 2001); doi: 10.1117/12.443037
Show Author Affiliations
Michelle Diane Chabot, Univ. of Texas at Austin (United States)
Troy C. Messina, Univ. of Texas at Austin (United States)
Vladimir Mancevski, Xidex Corp. (United States)
Casey W. Miller, Univ. of Texas at Austin (United States)
John T. Markert, Univ. of Texas at Austin (United States)

Published in SPIE Proceedings Vol. 4559:
MEMS Components and Applications for Industry, Automobiles, Aerospace, and Communication
Henry Helvajian; Siegfried W. Janson; Franz Laermer, Editor(s)

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