IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Microelectromechanical Systems (MEMS) Friday Sessions
       Session MM+BI+NS+EL+SS-FrM

Paper MM+BI+NS+EL+SS-FrM9
Fabrication Process and Resulting Structures for a Micron-Scale Force-Detected Nuclear Magnetic Resonance (NMR) Spectrometer

Friday, November 2, 2001, 11:00 am, Room 130

Session: New Frontiers in MEMS: NEMS and BioMEMS
Presenter: L.A. Madsen, California Institute of Technology
Authors: L.A. Madsen, California Institute of Technology
G.M. Leskowitz, California Institute of Technology
D.P. Weitekamp, California Institute of Technology
W. Tang, NASA Jet Propulsion Laboratory
T. George, NASA Jet Propulsion Laboratory
K. Son, NASA Jet Propulsion Laboratory
Correspondent: Click to Email
NMR is the most widely used method of analysis of chemical structure and dynamics at the millimeter length scale. In order to overcome the inherent poor sensitivity of traditional inductively detected NMR for small samples, we are developing the novel BOOMERANG@footnote 1@ method of force-detected NMR in a homogeneous magnetic field. Our experimental NMR results on liquid and solid 3 mm samples with a prototype spectrometer motivate the scaling of our detectors to observe samples < 100 microns in diameter. Achieving micron-scale detectors will bring about inexpensive NMR spectrometers with superior sensitivity for in-situ analysis, sub-monolayer surface NMR, and massively parallel studies on sample libraries. Ultimately, scaling of these detectors to the nano-scale may allow single-molecule NMR spectroscopy and imaging. We present a microfabrication process for BOOMERANG NMR detectors. This double-sided process utilizes deep RIE to define a Si beam fixed at both ends with a stress buttress at its center. High-aspect ratio NiFe or CoNiFe magnet structures are electrodeposited onto the backside of this beam. A combination of photoresist and oxide sacrificial layers allows ~1 micron spacing between a field compensation magnet and the moving detector magnet, and between the compensation magnet and the Si beam. Initial results of the 6-mask process are promising. We present patterned, electrodeposited magnets on the micro-oscillator substrate, as well as our efforts to characterize the micro-detectors and improve device yield. @FootnoteText@ @footnote 1@ Sol. St. Nucl. Magn. Reson. 11, 73 (1998).