Showing papers in "Sensors and Actuators A-physical in 1993"
TL;DR: A new valveless fluid pump has been designed and tested that consists of two fluid diffuser/nozzle elements on each side of a chamber volume with an oscillating diaphragm that creates a one-way fluid flow.
Abstract: A new valveless fluid pump has been designed and tested. The pump consists of two fluid diffuser/nozzle elements on each side of a chamber volume with an oscillating diaphragm. The vibrating diaphragm produces an oscillating chamber volume, which together with the two fluid-flow-rectifying diffuser/nozzle elements, creates a one-way fluid flow. A micropump prototype with a chamber diameter of 19 mm with conical diffuser/nozzle elements has been built and tested. The maximum liquid flow rate is 16 ml/min and the maximum pump pressure is 2 m H 2 O. The pump frequency is of the order of 100 Hz.
717 citations
TL;DR: Capacitive sensors for the detection of mechanical quantities all rely on a displacement measurement as mentioned in this paper, where the movement of a suspended electrode with respect to a fixed electrode establishes a changing capacitor value between the electrodes, and if the mechanical quantity controls the movable electrode, a sensor is realized.
Abstract: Capacitive sensors for the detection of mechanical quantities all rely on a displacement measurement. The movement of a suspended electrode with respect to a fixed electrode establishes a changing capacitor value between the electrodes. This effect can be measured and if the mechanical quantity controls the movable electrode, a sensor is realized. Since the value of the capacitor is directly related to its size, and a small capacitor means high noise susceptibility, capacitive sensors should be as large as possible. Capacitive pressure sensors have been developed with success for industrial applications, where large membrane sizes are not a critical issue. However, most centres of expertise in silicon sensors show an interest in exploiting silicon technology to produce capacitive pressure sensors as well. From the above, this miniaturization trend appears to be an unsound idea. On the other hand, the principle of capacitive sensors allows the realization of measuring systems with so far unknown performance. Indeed, the capacitive sensor reveals distinct advantages when compared to its piezoresistive counterpart: high sensitivity, low power consumption, better temperature performance, less sensitive to drift, etc. Nevertheless, only a minor fraction of the market for pressure sensors is taken up by capacitive-type sensors. When observing the characteristics of capacitive sensors, it may seem surprising to encounter so few devices in real-world applications. The reasons for the lack in breakthrough can be found in the design complexity and the requirements for a matched sensing circuit. This paper will extensively discuss the justification of the choice for this research effort, and will elaborate on the techniques to fabricate the devices based on electronic manufacturing procedures. Basically, silicon capacitive sensors differ from piezosensors in that they measure the displacement of the membrane, and not its stress! This has important implications on the final assembled device: less package-induced problems can thus be expected. However, a far more important issue is their extremely high sensitivity, together with a low power consumption. These issues make them especially attractive in biomedical implant devices, or in other telemetry applications, where power is not randomly available. So far, this is the only field of success for these sensors. However, due to the interesting detection principle, new fields of application emerge, offering unique and superior performance when compared to available sensors. Uniaxial accelerometers are a good example, where extremely high cross-sensitivity reduction can be obtained.
325 citations
TL;DR: In this article, the authors compare the theoretical predictions for two isolated rectangular plates oscillating normal to each other with measurements on a silicon microstructure that approximates such plates, representing squeeze numbers between zero and 1000, and flow regimes from molecular, through transition to viscosity dominated.
Abstract: Mathematical formulations of the effects of squeezed films of gas have been available for some years. We compare the theoretical predictions for two isolated rectangular plates oscillating normal to each other with measurements on a silicon microstructure that approximates such plates. A range of pressure from vacuum to atmospheric, and frequencies from d.c. to 50 kHz are employed, representing squeeze numbers between zero and 1000, and flow regimes from molecular, through transition to substantially viscosity dominated. Generally the agreement with predictions is good, though there is a small but significant difference in effective plate separation between low frequencies ( 10 kHz). Attention is drawn to the high degree of gas trapping between the plates at resonance, for all pressures investigated; the possibility of using this effect as a presssure sensor is noted. Phase measurements at low frequency provide a simple measurement of gas viscosity.
242 citations
TL;DR: In this paper, a simple to realize micro-liquid flow sensor with high sensitivity is presented, based on well known thermal anemometer principles, and an analytical model for the sensor behaviour applicable for gas/liquid fluids is presented.
Abstract: A simple to realise micro-liquid flow sensor with high sensitivity is presented. The sensor is based on well known thermal anemometer principles. An analytical model for the sensor behaviour applicable for gas/liquid fluids is presented. The realisation process of the sensor is described. Model and experimental results agree well. The sensor is simple to integrate with other micro-liquid handling components such as pumps, mixers, etc.
189 citations
TL;DR: In this paper, a new etching system of TMAH/IPA (isopropyl alcohol) is suggested and the influence of the addition of IPA to TMAHA solutions on their etching characteristics is presented.
Abstract: The main advantages of tetramethyl ammonium hydroxide (TMAH)-based solutions is their full compatibility with IC technologies. In this work a new etching system of TMAH/IPA (isopropyl alcohol) is suggested. The influence of the addition of IPA to TMAH solutions on their etching characteristics is presented. The etch rates of (100) oriented silicon crystal planes decreases linearly with decreasing the IPA concentration for all experimental conditions. Etch rates for TMAH/IPA solutions (10–45 μm/h) are lower than those for KOH/IPA solutions (30–100 μm/h) but they are still applicable for micromachining purposes. The etch rates of most commonly used masking layers in IC technologies has been investigated. Low-pressure chemical vapour deposited (LPCVD) Si 3 N 4 and thermally-grown SiO 2 have excellent stability in TMAH/IPA solutions. Low-temperature deposited silicon oxide (LTO) etch rates are low enough to be used as masking layers in anisotropic etching processes. Quality of etched surfaces is mainly dependent on TMAH wt.% concentration. For pure TMAH solutions the observed undercutting ratio (5–7) is much larger than in KOH case. The addition of IPA to TMAH solutions reduce the undercutting by a factor of more than 2 and leads to smoother surfaces of sidewalls etched planes. We have studied briefly the p ++ etch-stop characteristics by means of heavily boron-implanted layers. The etching selectivity with respect to high boron-doped silicon is improved in TMAH/IPA solutions. Implant doses used in our experiments (2 × 10 16 ion/cm 2 ) stands the etching during more than 90 min.
185 citations
TL;DR: In this paper, the buckling and rotation techniques are used to measure tensile and compressive strain in polysilicon thin-film structures, which can be easily measured using an array with different beam lengths.
Abstract: New stress-measurement devices for measuring both tensile and compressive strain in single structures have been realized. The investigation is concentrated on the development of two techniques: (i) buckling and (ii) rotation. The buckling technique is based on the buckling of a beam when exceeding a critical strain level. Therefore, an array with different beam lengths is required. The rotation technique, on the other hand, converts the extension or contraction of the material into a rotation, which can be easily measured. These structures have been modelled, simulated, and tested experimentally, using thin polysilicon films. Both techniques have been shown to be promising methods for simple and accurate on-chip thin-film strain measurements.
176 citations
TL;DR: In this article, it was shown that in ethanol solution the compounds FAA and TA can be measured and distinguished from phenylalaninol (FA) using a imprinted polymer membrane.
Abstract: Investigations of the usefulness of molecularly-imprinted polymers in sensor applications were undertaken. Thin polymer membranes containing molecular imprints against l-phenylalanine anilide were prepared and applied as sensing layer in field-effect capacitors. In this report some experimental results obtained for C-V measurements when the polymer membranes were exposed to l-phenylalanine anilide (FAA), tyrosinanilide (TA), and phenylalaninol (FA) in ethanol are presented. Despite some difficulties, it was shown that in ethanol solution the compounds FAA and TA can be measured and distinguished from FA using a imprinted polymer membrane.
146 citations
TL;DR: In this paper, the authors focused on sensor prototypes realized by industrial CMOS IC technology with post-processing micromachining, including thermally excited acoustic resonators, thermoelectric gas flow, infrared, and power sensors.
Abstract: Sensor design and fabrication using industrial IC technologies has the advantages of batch fabrication and on-chip interface circuitry. Sensors made by CMOS or bipolar IC technology have been demonstrated for magnetic, temperature and radiation measurands. Certain thermal, mechanical and chemical sensors can be realized by combining IC technologies with additional, compatible processing. We distinguish the methods of multiple project wafers, single project wafers, post-processing IC chips or wafers, and IC fabrication merged with sensor processing performed before, after, and in-between the regular IC processing steps. This paper is focused on sensor prototypes realized by industrial CMOS IC technology with post-processing micromachining. Examples include thermally excited acoustic resonators, thermoelectric gas flow, infrared, and power sensors, and a thermal conductivity sensor.
130 citations
TL;DR: In this paper, the design, fabrication and performance of a silicon microvalve for small gas flows is described, which consists of two micromachined components which are bonded together, one containing the gas flow inlet, the other part a deflectable silicon membrane.
Abstract: We report on the design, fabrication and performance of a silicon microvalve for small gas flows. It consists of two micromachined components which are bonded together. One part contains the gas flow inlet, the other part a deflectable silicon membrane. This membrane may be activated by a combination of electromagnetic and electrostatic forces. This principle is especially useful for minimizing the power consumption. The main experimental results are as follows: The maximum pressure against which the valve can fully operate is 160 mbar. With this pressure, a flow of up to 3 ml/min can be controlled. Typically, current pulses of 200 mA and voltage amplitudes of 30 V are applied for electromagnetic and electrostatic actuation, respectively. The switching time is below 0.4 ms.
109 citations
TL;DR: In this paper, two unmodified industrial CMOS processes have been used for the integration of highly interdigitated pn structures, and under forward bias these pn junctions emit narrow-band infrared light at 1160 nm with an electrical-to-optical power conversion efficiency of typically 10 −4.
Abstract: Two different unmodified industrial CMOS processes have been used for the integration of highly interdigitated pn structures. Under forward bias these pn junctions emit narrow-band infrared light at 1160 nm with an electrical-to-optical power conversion efficiency of typically 10 −4 . The same junctions show broad-band visible-light emission between 450 and 800 nm in the avalanche breakdown region under reverse bias with efficiencies of the order of 10 −8 . This is already enough for a first few practical applications as light-emitting devices (LEDs). No satisfactory explanation for this emission efrect, fitting all the experimentally observed electro-optical and physical properties of our silicon LEDS, has been found yet.
105 citations
TL;DR: In this paper, the kinetic bond model of Stengl et al. is applied to low-temperature bond strengthening and agreement between calculated and measured data points is established for silicon-wafer-bond strengthening in the 200-400 °C range.
Abstract: Silicon-wafer-bond strengthening in the 200–400 °C range can be successfully applied for wafers having temperature-sensitive device structures. The bond quality and specific surface energy of the bond have been studied experimentally with respect to the surface hydrophilization state. The kinetic bond model of Stengl et al. is applied to low-temperature bond strengthening and agreement between calculated and measured data points is established. Wafer bonding by means of static pressure is shown to be effective in the enhancement of the bond strength by overcoming most of the local waviness during room-temperature wafer bonding. Specific surface energies of 1.9 and 2.3 J/m2 can be reached using surface plasma-activated wafers in bond strengthening at 200 and 400 °C, respectively. A problem in low-temperature wafer-bond strengthening is the voids that are generated in the 200–700 °C range. Our results support the opinion that they are caused by interface water released in the bond reaction. Void-free bond strengthening is possible by the insertion of a shallow groove structure into the silicon or the oxidized silicon surface of one of the wafers.
TL;DR: In this paper, the authors investigated plasma oxidation of silicon in the reactive ion etching (RIE) mode as a pretreatment for silicon direct bonding (SDB) and obtained a bond strength of 1.3-2.7 J/m2, sufficient for assembling purposes.
Abstract: R.f. plasma oxidation of silicon in the reactive ion etching (RIE) mode is investigated as a pretreatment for silicon direct bonding (SDB). An ‘active oxide’ is formed on the surface, which can be wetted by water rinsing. The result is good adhesion of the wafer pairs to be bonded. A bond strength of 1.3–2.7 J/m2, sufficient for assembling purposes, is already obtained at temperatures of 450 °C.
TL;DR: In this article, a thin-film resistance strain gauge was developed for dynamic stress measurements up to 900 degrees C. The strain gauge consists of a NiCoCrAlY coating, insulating layer (Al2,O3), sensing layer (NiCr, PdCr), intermediate splicing layer (Pt), and a protective film (SiO2), and the masking of the layers, the splicing of the thin films to wires and the deposition technique on complex three-dimensional structures were presented.
Abstract: To respond to the industrial interest of aeroengine manufacturers in carrying out instrumentation techniques for blade vibration measurements, ONERA is developing thin-film resistance strain gauges suitable for dynamic stress measurements up to 900 °C. The strain gauge, deposited by r.f. sputtering onto nickel-based superalloys, is described. It consists of a NiCoCrAlY coating, insulating layer (Al2,O3), sensing layer (NiCr, PdCr), intermediate splicing layer (Pt) and a protective film (Al2,O3 or SiO2). The masking of the layers, the splicing of the thin films to wires and the deposition technique on complex three-dimensional structures are presented. The first electrical and mechanical properties of the sensing layers are described, as well as preliminary results concerning the thermal stability of the gauges.
TL;DR: In this article, the authors report several integrated thermoelectric infrared sensors on thin silicon oxide/nitride microstructures realized by industrial CMOS IC technology, followed by one compatible maskless anisotropic etching step.
Abstract: We report several integrated thermoelectric infrared sensors on thin silicon oxide/nitride microstructures realized by industrial CMOS IC technology, followed by one compatible maskless anisotropic etching step. No additional material is needed to enhance infrared absorption in the spectral region between 8 and 14 μm, since the passivation layer, as provided by the CMOS process, shows significant absorption bands. We compare aluminium/polysilicon thermopiles with n-poly/p-poly thermopiles. Our sensors show responsivities between 12 and 72 V/W, normalized detectivities between 1.7 × 10 7 and 2.4 × 10 7 cm√Hz/W and time constants of 10–20 ms.
TL;DR: The concept of regionally strategic sensors for a class of distributed parameter systems is introduced and the spatial structure and location of the sensors are emphasized in order that regional observability can be achieved.
Abstract: In various distributed systems we are interested in the knowledge of the state of a given sub-region. The aim of this paper is to introduce the concept of regionally strategic sensors for a class of distributed parameter systems. This emphasizes the spatial structure and location of the sensors in order that regional observability can be achieved. For different geometrical situations we give the characterization of regional strategic sensors. We also give the dual results for the characterizations of regional strategic actuators.
TL;DR: In this paper, a new method to simulate the sensitivity and frequency response of capacitive microphones has been developed, which is used in combination with equivalent circuits to evaluate mechanical, electrostatic and acoustic effects.
Abstract: A new method to simulate the sensitivity and frequency response of capacitive microphones has been developed. Finite-element analysis is used in combination with equivalent circuits to evaluate mechanical, electrostatic and acoustic effects. The simulation method has been applied to a condenser microphone in monocrystalline silicon. The design has a thin and highly perforated backplate in combination with a small air gap of 2 μm. Sensitivities in the range 1–5 mV/Pa have been recorded with a bias voltage between 5 and 13 V. The device has a first resonance at 27 kHz. The measured results are in good agreement with the results obtained with the new simulation method.
TL;DR: In this paper, double polysilicon thermopile gas flow sensor was implemented in an industrial CMOS process, which uses the Seebeck effect between ndoped and p-doped poly-silicon to prevent a pnjunction between the two materials.
Abstract: We report the first implementation of a double-polysilicon thermopile gas flow sensor in an industrial CMOS process. The sensor uses the Seebeck effect between n-doped and p-doped polysilicon as provided by the CMOS process. In order to prevent a pn-junction between the two materials the polysilicon lines are connected through aluminium contacts. Thermal isolation is achieved by placing the thermopile on a thin silicon dioxide membrane. Sensitivity with respect to nitrogen flow velocity and heating power is 0.36 mV/sccm/mW in the linear range, i.e. one order of magnitude better than our previous CMOS polysilicon/aluminium thermopile sensors ( Sensors and Actuators A, 25–27 (1991) 577-581).
TL;DR: In this article, a convex corner compensation for etching in aqueous KOH using only strips is presented turns and branches are used to control the etching front on the strip surface for better compensation quality.
Abstract: In this paper a scheme of convex corner compensation for etching in aqueous KOH using only strips is presented Turns and branches are used to control the etching front on the strip surface for better compensation quality The design rules as well as the effects of turning and branching on the effective compensation length are presented The etching fronts on the bottom are investigated by experiment Applications of the new structures are shown
TL;DR: In this article, a new resonating sensor for gas pressure is described, which measures the resonance frequency of a silicon microstructure that contains a thin film of gas trapped in the structure by the squeeze-film effect.
Abstract: A new resonating sensor for gas pressure is described. The device measures the resonance frequency of a silicon microstructure that contains a thin film of gas trapped in the structure by the squeeze-film effect. The gas is confined in the structure during an oscillation cycle only by its viscosity. It exerts a measurable influence on the resonance frequency at a pressure of 10−2 mbar, and provides the dominant spring force at pressures near one atmosphere, where the short-term stability of the sensor is of the order 1/30 mbar. We present data showing that the resonance frequency is species independent, which implies that the compressions are isothermal. Damping, however, depends on the gas viscosity, and the measurement of the oscillator Q value allows species to be identified. In the device, the oscillating diaphragm is not under a pressure load so that long-term creep is not a consideration. Further, at higher pressures, the device directly measures the spring constant of a defined volume of gas with only a small contribution from the silicon spring constant. It therefore has potential as a long-term reference of pressure.
TL;DR: In this paper, a new in-line fiber-optic sensor based on the excitation of surface plasmons in a thin metal film deposited in the polished cladding of the fiber is presented.
Abstract: A new ‘in-line’ fibre-optic sensor based on the excitation of surface plasmons in a thin metal film deposited in the polished cladding of the fibre is presented. Optical-power transmission characteristics of the device, for TM-polar- ized light, have been both experimentally and theoretically investigated. The obtained results show the feasibility of practical designs with in-line fibre-optic configuration for a large range of optical sensor applications.
TL;DR: In this paper, a method was developed to bond 3-inch borosilicate sputter-coated silicon wafers to silicon wafer coated either with aluminium, silicon dioxide, polysilicon or silicon nitride.
Abstract: Silicon to silicon wafer bonding by use of sputter deposited borosilicate film is a promising mounting method for micromechanical components. This method has been developed to bond 3 inch borosilicate sputter coated silicon wafers to silicon wafers coated either with aluminium, silicon dioxide, polysilicon or silicon nitride. The bondings were performed at temperatures ranging from 300 to 400 °C which enables application of this technique on metallised devices. The bond strengths of the different samples bonded with these methods are all in the region 5–25 MPa. Some samples were exposed to water for 300 h to test the media compatibility, and some samples were thermal shock tested by repeatedly exposing to liquid nitrogen. No significant difference in bond strength has yet been verified statistically for the different sample configurations. We have also observed good correlation between destructive bond strength testing and non-destructive infrared microscope inspection.
TL;DR: In this paper, an integrated silicon capacitive accelerometer has been developed with CMOS and micromachining technology, which is 3.7 × 4.5 × 0.9 mm 3 in size.
Abstract: An integrated silicon capacitive accelerometer has been developed with CMOS and micromachining technology. The accelerometer chip has glass—silicon—glass structure and is 3.7 × 4.5 × 0.9 mm 3 in size. A silicon seismic mass is suspended with silicon-oxinitride beams in full symmetry. The sensor capacitance is formed between the silicon mass and a metal electrode on the upper glass. A CMOS capacitance to frequency (C–F) converter is integrated on the silicon chip. The circuit is designed to be stable to temperature and supply voltage. The circuit has a reference capacitor in it, and the drift of the circuit is compensated by the information obtained when the circuit is connected to the reference capacitor. The output frequency of the accelerometer chip varies linearly with acceleration. The force-balancing system has been realized using the accelerometer chip and an outer phase-locked-loop (PLL) servo circuit. The output voltage varies linearly with acceleration, and the sensitivity and offset of the output voltage can be adjusted with the outer circuit parameter.
TL;DR: In this paper, a comb actuator with a folded beam suspension consisting of 0.4 μm wide, 2 μm thick and 300 μm long beams allowed for a small spring constant around 6 mN/m.
Abstract: The flexibility of the suspension is a key factor if the driving voltage of electrostatic micro comb actuators is to be reduced. We have fabricated and tested surface micromachined polysilicon comb actuators with submicrometrewide suspensions. For example, a comb actuator with a folded beam suspension consisting of 0.4 μm wide, 2 μm thick and 300 μm long beams allowed for a small spring constant around 6 mN/m. As a result, only low voltages are required for actuation, e.g., 14.5 V for a 7.3 μm displacement. In addition, we have constructed and characterized a novel actuator, named the sarcomere actuator, where several comb actuators are placed in parallel; it allows the driving force at a given voltage to be increased by almost a factor of three. Based on the high flexibility of the suspension, we have fabricated a comb-driven xy-microstage. Tests with this prototype device show that controlled two-dimensional positioning in the range of several micrometres and with a precision of better than 80 nm can be achieved.
TL;DR: In this article, the friction coefficient between tyre and road can be calculated by the measurement and evaluation of influencing parameters, such as road texture, wetness and ice on road surfaces.
Abstract: The friction coefficient between tyre and road can be calculated by the measurement and evaluation of influencing parameters Non-contact sensors for road texture, wetness and ice on road surfaces are presented A prediction model based on measured parameters gives a reliable value of the coefficient of friction, μ
TL;DR: In this article, a silicon liquid velocity sensor fabricated by using an industrial bipolar process combined with micromachining is described, which is sensitive to variations of a forced heat flow modulated by the liquid velocity.
Abstract: This paper reports on modeling and characterization of a silicon liquid velocity sensor fabricated by using an industrial bipolar process combined with micromachining. For applications in the biomedical field, miniature sensors are needed for measuring flow velocities in the range up to 2 m/s. In order to measure such small velocities, we have developed a sensor which is sensitive to variations of a forced heat flow modulated by the liquid velocity. As a large temperature gradient will change the properties of biological liquids, this sensor uses small temperature differences of about 1 to 10 °C. A high average sensitivity of 10 mV/(m/s) has been measured. The overall dimensions of the chip are 2.0 mm × 1.6 mm × 0.4 mm.
TL;DR: In this article, the authors used a 400 nm thick silicon layer as a support for the absorbing silver film with a sheet resistance of 150 Ω/□, evaporated onto the rear side of the silicon layer.
Abstract: In order to achieve the maximal sensitivity of a thermal IR sensor, the incident light must be efficiently absorbed. This may be done either by the sensor material with its own electrodes or by an additional absorber structure. Freely suspended thin metal films are known to act as wide-band absorbers for IR radiation. Prepared on the solid surface of the sensor, the absorbing properties of the metal layer are, however, strongly influenced by the dielectric function of the sensor material. Results are presented for thermoelectric and pyroelectric sensors. For the thermoelectric sensor, a 400 nm thick silicon layer is used as a support for the absorbing silver film with a sheet resistance of 150 Ω/□, evaporated onto the rear side of the silicon layer. This absorber has an absorbance of nearly 50% independent of the wavelength over the whole IR range. For pyroelectric sensors two examples of absorbers on PVDF are presented. The first is a broad-band absorber and has an absorbance of about 50% within the wavelength region 3–200 μm. The other is a selective absorber and has an absorbance of about 90% within the region 7–15 μm. The selective absorber is completely opaque and can be realized by means of a PVDF film with a thickness of about 2 μm, covered on both sides by metal films. This structure may serve as an excellent absorber for a crystalline pyroelectric sensor.
TL;DR: In this paper, the DIMES-01 BIFET baseline process is described in relation to their application in integrated silicon sensor research and development. And the possibilities of introducing special sensor process modules and steps are treated.
Abstract: The DIMES-01 BIFET baseline process is presented. The process and devices are described in relationship to their application in integrated silicon sensor research and development. In particular, the possibilities of introducing special sensor process modules and steps are treated.
TL;DR: In this paper, a fiber-optic displacement sensor that is compensated for variations in light-source intensity as well as for losses in the fibers is described, and the compensation mechanism of the twin-receiving-fiber displacement sensor is analyzed.
Abstract: This paper describes the evaluation of a fiber-optic displacement sensor that is compensated for variations in light-source intensity as well as for losses in the fibers. On the basis of the intensity distribution function of the output optical field formed by the source fiber end, the compensation mechanism of the twin-receiving-fiber displacement sensor is analyzed. It is shown theoretically that the ratio of the outputs of a pair of detecting fibers is independent of the light-source intensity and losses in the fiber system. Results are presented that confirm this.
TL;DR: In this article, the sources of error when measuring pressure with a silicon resonant sensor were described in the context of a new precision barometer, which is used to measure pressure in a silicon-resonant sensor.
Abstract: The sources of error when measuring pressure with a silicon resonant sensor are described in the context of a new precision barometer.
TL;DR: In this paper, the effects of photothermal excitation and self-excitation of silicon micro-resonators are investigated. And the temperature compensation techniques are analyzed. But the authors focus on the effect of photothermally excited flexural vibrations of the microresonator under the action of modulated optical radiation.
Abstract: Fiber optic sensors with a silicon microresonator acting as a sensitive element have been proposed for measurement of many physical parameters. The basic principle is that the measured value changes the resonance frequency of the microresonator. The flexural vibrations of the microresonator are excited photothermally under the action of modulated optical radiation. The interferometric optical feedback may cause self-oscillation of the microresonator even without light modulation. This is a theoretical paper devoted to consideration of the effects of photothermal excitation and self-excitation of silicon microresonators. For the first time the mechanism of parametric excitation of microresonators is investigated. The temperature compensation techniques are analyzed.