AVS 52nd International Symposium
    Vacuum Technology Wednesday Sessions
       Session VT-WeM

Paper VT-WeM3
The Nanogate as a Nanoscale Variable Flow Leak Element

Wednesday, November 2, 2005, 9:00 am, Room 201

Session: Gas Flow and Pump Technology
Presenter: P.J. Abbott, NIST
Authors: J.R. White, NIST
P.J. Abbott, NIST
M.J. Tarlov, NIST
A.H. Slocum, Massachusetts Institute of Technology
Correspondent: Click to Email
We present a variable flow leak artifact based on an ultra-high precision MEMS-based valve called a "Nanogate." Many critical industrial processes rely on generating and delivering accurate and precise flows of gas. Examples include leak testing of nuclear containment vessels, gas delivery in semiconductor processing, quantifying the emission of ozone-depleting chlorofluorocarbons, food processing and packaging, and testing of medical implants such as pacemakers. The flows of gas required for these applications span a very broad range, from as low as 10@super-14@ moles per second to higher than 10@super-6@ moles per second, and generally require several instruments to cover it; among these are mass flow controllers, metal capillary leak elements, and permeation leak elements. In contrast, the Nanogate can generate extremely low gas flows over several orders of magnitude, for any gas of interest, and offers the advantage of precise control of the flow rate due to the Nanogate's ability to change its opening in controlled two angstrom steps. Testing of the device with helium, carbon dioxide, and methane has shown good agreement with theory. Calibration results with several gases using the NIST low gas flow standard will be discussed.