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This paper presents the design, measured data, and systematic analysis of spiral embedded inductors fabricated on standard organic substrates using low-cost, large-area MCM-L technology. Several configurations for inductors were investigated to optimize the inductor layout dimensions such as conductor width, number of turns, inner diameter, spacing between inductor and ground, and inductor area. A maximum Q of 100 was measured for a 3.6 nH inductor at 1.8 GHz on an organic substrate with a self resonance frequency of 10.6 GHz within an inductor core area of 0.72 mm/sup 2/. The effects of configurational variables on inductor characteristics such as quality factor, self-resonance frequency, and inductance are discussed. High-Q inductors embedded on organic substrates can find numerous RF and microwave system-on-package (SOP) applications, such as VCOs, IF/RF bandpass filters, LNAs, etc., in which IC chips are flip-chip mounted on the package substrate.

This paper presents a high sensitivity silicon micromachined capacitive accelerometer fabricated using a three mask, dissolved wafer process. High electrical sensitivity is obtained by using high aspect-ratio comb fingers with narrow air gaps of 2 /spl mu/m and large overlap area of 12 /spl mu/m/spl times/300 /spl mu/m. Torsional suspension beams 150 /spl mu/m long with a cross-sectional area of 12 /spl mu/m/spl times/3 /spl mu/m are used to improve the mechanical gain (form factor). By using a varying overlap area method, the dynamic range, the pull-in voltage and the bandwidth are improved. The fabricated accelerometers yielded sensitivities of 263-300 mV/g, a nonlinearity less than 0.2% over a range of -4 g to +3 g, a full scale range of -4 g to +6 g and pull-in voltages greater than 8 V. A 3-dB cut-off frequency of 30 Hz was measured in air. The minimum resolution measured by the readout electronics was 0.077 g.

This paper presents a detailed analysis on the design and scaling limits of vibrating ring gyroscopes and their implementation using a combined bulk and surface micromachining technology. A high aspect-ratio p++/polysilicon trench-refill fabrication technology has been used to realize the 30-40 /spl mu/m thick polysilicon ring structure with 0.9 /spl mu/m ring-to-electrode gap-spacing. The theoretical analysis of the ring gyroscope shows that by taking advantage of the high quality factor of polysilicon, sub-micron ring-to-electrode gap spacing, high aspect ratio polysilicon ring structure produced using deep dry-etching, and the all-silicon feature of this technology, tactical grade vibrating ring gyroscopes with random walk as small as 0.05 deg//spl radic/h can be realized, providing several orders of magnitude improvement in performance.

In this paper, radio frequency (RF) ultra-stiff electromechanical resonators are introduced and compared with their ultra-light counterparts. RF ultra-stiff resonators with dimensions in the low end of the micrometer scale can yield UHF frequencies (0.33 GHz) by operating at their higher order flexural modes. However, electrostatic actuation and capacitive sensing of ultra-stiff resonators will require nanoscale airgaps. The HARPSS (high aspect-ratio combined poly and single crystal silicon MEMS technology) fabrication process presented in this paper is an all-silicon process that is capable of producing capacitive silicon resonators (poly and single-crystalline) with lateral gap spacing as small as 10 nm between the resonating structure and the silicon electrodes, without the need for nano-lithography.

This paper presents an all-silicon, single wafer high aspect-ratio dry-release MEMS technology capable of producing 10-100's of microns thick, electrically isolated 3-D silicon microstructures. This process utilizes polysilicon as the structural material and is capable of producing very thick polysilicon and silicon electrodes using deep reactive ion etching of silicon. Various size capacitive air-gaps ranging from sub-micron to tens of microns can be realized in this technology. Using a bent-beam strain gauge, residual stress in 80 /spl mu/m thick, 4 /spl mu/m wide trench-refilled vertical polysilicon beams fabricated through this technology have been measured to be zero. 300 /spl mu/m long clamped-clamped beam resonators have shown quality factors as high as 85,000 in 1m Torr vacuum. This technology provides features required for high performance vibratory gyroscopes. The all-silicon feature of the technology improves long-term stability and temperature sensitivity; fabrication of large area, vertical electrodes with sub-micron gap will increase the sensitivity by orders of magnitude. Larger air-gaps can accommodate large drive amplitudes for increased Coriolis acceleration.

This paper reports on the fabrication and characterization of single crystal silicon (SCS) in-plane capacitive resonators with submicron gap spacing using the HARPSS process. The resonating element is made out of single crystal silicon and the drive and sense electrodes are made out of trench-refilled polysilicon, hence yielding an all-silicon microresonator with potentially better temperature and long-term stability. The capacitive gap is defined by a sacrificial oxide layer, which can be potentially reduced to the ten’s of nanometer range (700nm reported in this paper). Quality factor as high as 67,000 was measured in 1mTorr vacuum for the 40kHz fundamental resonance frequency of a clamped-clamped beam SCS HARPSS resonator. A 510µm long, 5.5µm wide, 20µm thick clamped-clamped beam resonator was operated in its third resonance mode at 1MHz and demonstrated a Q of 11,000 under vacuum. Electrostatic tuning characteristics of the resonators have been measured and reported.

This paper reports on a low-cost low-temperature (

This paper presents the design, fabrication and testing of capacitive copper RF MEMS switches with various hinge geometries, fabricated on high-resistivity silicon substrates. The switches were fabricated using a simple low-cost four-mask process and 0.6-1.0 /spl mu/m thick membranes were made out of sputtered copper. The capacitive airgap in between the membrane and the signal line is 1.5-2.0 /spl mu/m. The lowest actuation voltage measured on the fabricated switches is 9 V. The measured insertion loss of a fabricated switch and its associated transmission time was 0.9 dB (mainly contributed by the transmission line itself) and the isolation was measured to be 25 dB at 40 GHz.

Drive and Control This paper presents the fabrication and testing of a high aspect-ratio 80um tall polysilicon ring gyroscope (PRG) fabricated using a new dry-release poly-silicon MEMS technology. This single-wafer technology is capable of producing electrically isolated vertical electrodes as tall as the main body polysilicon structure (50 to 100’s urn tall) with various size air-gaps ranging from sub-micron to tens of microns. An open-loop sensitivity of 200pVldegfsec in a dynamic range of +250 degfsec was measured under low vacuum level for a prototype device tested in hybrid format. The resolution for a prototype sensor with a quality factor (Q) of 1200, drive amplitude of O.l5pm, and sense node parasitic capacitance of 2pF was measured to be less than 1 deg/sec in 1Hz bandwidth. Elimination of the parasitic capacitance and improvement in the quality factor of the ring structure will improve the resolution to 0.01 deg/sec in 1Hz bandwidth. Three hundred microns long clamped-clamped beam resonators fabricated in this technology have shown measured quality factors as high as 85,000 in 1mTorr vacuum.

Capacitive bulk acoustic wave x, y and z-axes gyroscopes implemented on (100) and (111) silicon substrates are disclosed. Exemplary gyroscopes comprise a handle substrate, a bulk acoustic wave resonator element supported by the handle substrate, and a plurality of electrodes surrounding and separated from the resonator element by very small capacitive gaps. The electrodes can excite and detect at least two degenerate bulk acoustic wave resonant modes in the resonator. Advantages include reduced size; higher Q, which improves noise and bias stability; larger bandwidth, and improved shock resistance. In addition, the high Q is maintained in atmospheric or near-atmospheric pressure which reduces the cost and complexity of the wafer-scale packaging of the gyroscope.

Fully integrated low insertion loss micromachined band-pass filters are designed and fabricated on the silicon substrate (ρ = 10‐20 � cm, er = 11.9) for UHF applications. Filters are made of silver, which has the highest conductivity of all metals, to minimize the ohmic loss. A detailed analysis for realizing low insertion loss and high out-of-band rejection filters using elliptic magnitude characteristics is presented, and a comprehensive model to take into account inductive parasitics of the interconnects is developed. Temperature characteristics of the filters are measured and show stable performance. The presented filters are different from the previously reported lumped element filters in that all filters are fully integrated on silicon substrate and occupy a remarkably smaller die area. Two filters are fabricated using the silver micromachining technique with center frequencies at 1.05 and 1.35 GHz. The filters have a constant 3 dB bandwidth of 300 MHz (28.6% and 22.2%) and an insertion loss of 1.4‐1.7 dB. The low insertion loss and CMOS compatibility make the presented filters suitable candidates for radio frequency integrated circuits. (Some figures in this article are in colour only in the electronic version)

This paper demonstrates a metal-organic thin-film encapsulation technique based on the photolithography of multiple layers of positive-tone photo-definable polymer. This encapsulation process, performed at low temperatures (

Disclosed are high frequency, vertical silicon bulk acoustic resonators. Resonator structures having a relatively large transduction areas fabricated using a HARPSS fabrication process provide for high frequency capacitive resonators with significantly low impedance values. Impedance values as low as a few kilo-Ohms to sub-kilo-Ohm and quality factors in the range of 20,000 to 90,000 in the VHF range have been achieved for a first thickness mode of fabricated vertical silicon bulk acoustic resonators. Resonant frequencies as high as 983 MHz have been demonstrated for higher third thickness modes of the vertical silicon bulk acoustic resonators.

Vertical Hall sensors have been fabricated using a new process combining deep-RIE silicon trench etching and anisotropic TMAH silicon wet etching to precisely define the sensor's active area. The demonstrated release of the bottom of the devices with a wet etching step results in a well-defined and uniformly doped active area. The trench-defined vertical Hall sensors show a very high current related sensitivity of up to 1000 V/AT, a non-linearity of 0.06% FSO, and a residual offset (after spinning current offset reduction) of about 0.5 mT. A method for etching the polysilicon inside the trenches using XeF/sub 2/ without an additional mask is demonstrated on an SOI wafer. While the technology is demonstrated for vertical Hall sensors, it is also well suited for the fabrication and release of trench-defined MEMS, such as thin beams.

This paper reports, for the first time, on thin-film piezoelectric-on-diamond composite bulk acoustic resonators. These resonators benefit from the large elastic modulus of the nano-crystalline diamond to increase the resonance frequency, and the high electromechanical coupling of the piezoelectric transduction to reduce the motional impedance. More than 1.8times increase in the resonance frequency is measured for devices fabricated on 2 mum thick diamond compared to the same size devices made on 6 mum thick silicon on insulator substrate. A device with 5 mum feature size exhibits a high resonance frequency of 1.2 GHz. A small motional impedance of 225 Omega is reported for a device operating at 173 MHz. The temperature coefficient of frequency (TCF) is measured to be as small as -2 ppm/degC as a result of including an oxide layer in the device structure.