MICROFABRICATION OF CYLINDRICAL ION TRAP MASS SPECTROMETER ARRAYS FOR HANDHELD CHEMICAL ANALYZERS

A new microfabrication method for micro-cylindrical ion trap (μ-CIT) mass spectrometer arrays (r o , z o ≅ 360 μm) is presented along with a strategy for incorporating integrated high-field emission electron sources for ionization. Simulations of the performance of μ-CITs were used to guide the geometrical design of the array, and process flows for microfabrication in silicon were developed and optimized for reduced capacitance. The microfabrication process is described in detail along with initial test results. Field emission sources were also fabricated in silicon using an edge-to-edge emission strategy to improve robustness in moderate vacuum environments. Simulations were also used to guide the design of the field emitter arrays. The microfabrication process is described and initial field emission data are presented. Strategies for further optimization and integration are also briefly discussed.

[1]  R. Graham Cooks,et al.  SPECIAL FEATURE : PERSPECTIVE Miniature mass analyzers , .

[2]  R. Short,et al.  Environmental chemical mapping using an underwater mass spectrometer , 2004 .

[3]  Matthew Glenn Blain,et al.  Towards the hand-held mass spectrometer: design considerations, simulation, and fabrication of micrometer-scaled cylindrical ion traps , 2004 .

[4]  Shekhar Bhansali,et al.  Fabrication and testing of a miniature cylindrical ion trap mass spectrometer constructed from low temperature co-fired ceramics , 2006 .

[5]  Ramsey,et al.  Field-emission cold-cathode el source for a microscale ion trap mass spectrometer , 2000, Analytical chemistry.

[6]  D. Dahl.  simion for the personal computer in reflection , 2000 .

[7]  G. Petzold,et al.  Surface microstructure/miniature mass spectrometer:.processing and applications , 1998 .

[8]  R. Fowler,et al.  Electron Emission in Intense Electric Fields , 1928 .

[9]  V. Garkanian,et al.  Miniature, high-resolution, quadrupole mass-spectrometer array , 1997 .

[10]  J. Pawliszyn,et al.  On-site environmental analysis by membrane extraction with a sorbent interface combined with a portable gas chromatograph system , 2005 .

[11]  D. Polla,et al.  Development of edge field emission cold cathodes based on low work function Cu–Li alloy coatings , 2000 .

[12]  Kenneth R. Shoulders,et al.  Microelectronics Using Electron-Beam-Activated Machining Techniques , 1961, Adv. Comput..

[13]  R. Cooks,et al.  Miniature mass analyzers , 2000, Journal of mass spectrometry : JMS.

[14]  W. Whitten,et al.  Microfabricated quadrupole ion trap for mass spectrometer applications. , 2006, Physical review letters.

[15]  W. Whitten,et al.  High-pressure ion trap mass spectrometry. , 2004, Rapid communications in mass spectrometry : RCM.

[16]  Heinz H. Busta,et al.  Vacuum microelectronics-1992 , 1992 .

[17]  R. Cooks,et al.  Geometry optimization for the cylindrical ion trap: field calculations, simulations and experiments , 2005 .

[18]  R. Synovec,et al.  Recent Advances in Instrumentation for Gas Chromatography , 2005 .

[19]  George N. Fursey,et al.  Field Emission in Vacuum Microelectronics , 2005 .

[20]  B. C. Barish,et al.  K+N charge-exchange scattering at 1.94 GeV/c , 1972 .

[21]  R. Cooks,et al.  A parallel miniature cylindrical ion trap array , 2000, Analytical chemistry.

[22]  K. R. Williams,et al.  IC-processed hot-filament vacuum microdevices , 1992, 1992 International Technical Digest on Electron Devices Meeting.

[23]  Carolina Ribbing,et al.  Field-emitting structures intended for a miniature X-ray source , 2000 .

[24]  Jane P. Chang,et al.  Field emission characteristics of a tungsten microelectromechanical system device , 2005 .

[25]  Young Hee Lee,et al.  Fully sealed, high-brightness carbon-nanotube field-emission display , 1999 .

[26]  Qingyu Song,et al.  Handheld rectilinear ion trap mass spectrometer. , 2006, Analytical chemistry.

[27]  R. J. Ferran,et al.  High‐pressure effects in miniature arrays of quadrupole analyzers for residual gas analysis from 10−9 to 10−2 Torr , 1996 .

[28]  S Boumsellek,et al.  Trade-offs in miniature quadrupole designs , 2001, Journal of the American Society for Mass Spectrometry.

[29]  S. Itoh,et al.  Influences of gases on the field emission , 1993 .

[30]  T. Croley,et al.  Simulation of ion trajectories in a quadrupole ion trap: a comparison of three simulation programs , 1999, Journal of mass spectrometry : JMS.

[31]  Samuel E. Tolley,et al.  Miniature toroidal radio frequency ion trap mass analyzer , 2006, Journal of the American Society for Mass Spectrometry.

[32]  W. D. Palmer,et al.  Silicon field emitter cathodes: Fabrication, performance, and applications , 1998 .

[33]  R. Syms,et al.  Silicon based quadrupole mass spectrometry using microelectromechanical systems , 2001 .

[34]  C. Spindt,et al.  Physical properties of thin‐film field emission cathodes with molybdenum cones , 1976 .