The NanoGate: A device for nanometer control of the separation between two plates Prof. Alex Slocum Prof. Jeff Lang Hong Ma Alex Sprunt James White Xue’en Yang Massachusetts Institute of Technology June 28, 2002

Nanogate The Nanogate is a device that precisely meters the flow of tiny amounts of fluid. –Precise control of the flow restriction is accomplished by deflecting a highly polished cantilevered plate. –The opening is adjustable on a sub-nanometer scale, limited by the roughness of the polished plates. The Nanogate can be fabricated on a macro-, meso- or micro- (MEMs) scale. –This research grew out of understanding of flow metering garnered from years of hydrostatic bearing research This research was initially funded by an NSF award, number The Center for Bits and Atoms is funding the continued development of the Nanogate technology as it evolves into the FractureGate Possible fuel injector application?

Surface Creation Fracture –Must be done slowly –Surfaces will be matched (no plasticity) –Even “mirror” regions not atomically smooth Stress Corrosion Cracking –0.12 nm surface roughness independent of crystal orientation –K. Minoshima, S. Inoue, T. Terada, and K. Komai, “Influence of Specimen Size and Sub-Micron Notch on the Fracture Behavior of Single Crystal Silicon Microelements and Nanoscopic AFM Damage Evaluation,” Mat. Res. Soc. Symp. Vol. 546, pp , PolishedStress Cracked J. Connally and S. Brown, “Micromechanical Fatigue Testing,” Experimental Mechanics, Vol 33, No. 2 (June 1993)

Concept Etch manifold wafer Bond wafers DRIE through Break w/external actuator –=FractureGate In silicon, surfaces would be matable

Bench Level Experiment Insight into variables that affect stress corrosion cracking, i.e. stress, humidity, temperature AFM study of the surfaces Zipper Specimen Flexure Pivot Zipper Electrode Beam Pull-in Assist

Applications Microfluidics Variable Capacitor Physics in Gap Experiments Alternate Universes!?