CAD image of a typical H1 device. No substrate is shown in this figure. The springs also serve as electrical connections from the center plate to the external bonding pads on the chip.
SEM pictures of a typical device. An overall view of an H2 device is shown in the top left figure. The top right figure shows half of the same device. The bottom left figure shows a more detailed view of the spring of an H1 device at its anchor point with the substrate. A close up look at the comb-electrode fingers is displayed in the bottom right figure.
Top: Topography of the surface of the Poly0 layer in a typical device. Bottom: Histogram of heights from the topography of the surface of a device. The solid line represents a fit to a Gaussian.
Top: Normalized autocorrelation function calculated from the topography of the Poly0 surface in a typical device. Bottom: One-dimensional normalized autocorrelation function averaged from different spots on the same device and from different devices contained in the same chip.
Circuit diagram for the capacitance bridge technique employed. An external ratio transformer is used as a tunable inductive voltage divider along with the two capacitors formed by the two sets of electrodes at the sides of the device.
Vibrational modes and their corresponding frequencies for an H1 device. (a) shear mode. (b) Out-of-plane mode. (c) pivot mode about y axis. (d) pivot mode about x axis.
Top: Amplitude (a) and resonance frequency (b) as a function of bias voltage for the shear mode of an H1 device. Bottom: Amplitude (c) and resonance frequency (d) as a function of bias voltage for the pivot mode of an H1 device. The lines represent a fit to a parabola. The resulting equations for the fit are displayed in each graph.
Top: Q-factor and shear mode frequency of device H1 m as a function of pressure. Bottom: Q-factor and shear mode frequency of device H2 as a function of pressure
Top: Damping coefficient as a function of pressure for device H1. Bottom: Damping coefficient as a function of pressure for device H2. Calculated curves are shown for the damping due to the film (bottom), the top, and the fluid between the fingers.
Damping coefficient as a function of pressure for both devices, H1 and H2, as a function of K n . The vertical dashed lines separate the hydrodynamic, crossover and ballistic regimes.
Absorption (a) and dispersion (b) curves for an H1 device immersed in liquid 4He at different temperatures and at 2 bar pressure. Absorption (c) and dispersion (d) for an H2 device immersed in liquid 3He at different temperatures and at 3 bar pressure.
(a) Absorption curves for an H1 device immersed in normal 3He at different excitations and T = 276 mK. (b) Absorption curves in normal 3He rescaled by the excitation voltage. (c) Absorption curves for an H1 device immersed in superfluid 3He at different excitations and T ≈ 0.3 mK. (d) Absorption curves in superfluid 3He rescaled by the excitation voltage.
Thickness of the different layers used in PolyMUMPs.
Calculated device properties from layout geometry
Resonance frequencies and measured Q-factors in high vacuum (∼3 mTorr).
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