Micromachined convective accelerometers in standard integrated circuits technology

Milanović, V.; Bowen, E.D.; Zaghloul, Mona; Tea, N. H.; Suehle, John S.; Payne, Beverly F.; Gaitan, Michael

doi:10.1063/1.125803

Cited by 73 publications

(31 citation statements)

References 3 publications

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“…Similarly, the working principle of a convective accelerometer was based on the sensing of a temperature difference that is caused by a change in free convective flow due to acceleration (Milanovic et al [17] and Luo et al [18]). Free convective flows were caused by the buoyant forces generated by the thermal difference between a heated element in the device and the surrounding gas.…”

Section: Review Of Modeling Approachesmentioning

confidence: 99%

On heat transfer at microscale with implications for microactuator design

Ozsun¹,

Alaca²,

Yalçınkaya³

et al. 2009

J. Micromech. Microeng.

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The dominance of conduction and the negligible effect of gravity, and hence free convection, are verified in the case of microscale heat sources surrounded by air at atmospheric pressure. A list of temperature-dependent heat transfer coefficients is provided. In contrast to previous approaches based on free convection, supplied coefficients converge with increasing temperature. Instead of creating a new external function for the definition of boundary conditions via conductive heat transfer, convective thin film coefficients already embedded in commercial finite element software are utilized under a constant heat flux condition. This facilitates direct implementation of coefficients, i.e. the list supplied in this work can directly be plugged into commercial software. Finally, the following four-step methodology is proposed for modeling: (i) determination of the thermal time constant of a specific microactuator, (ii) determination of the boundary layer size corresponding to this time constant, (iii) extraction of the appropriate heat transfer coefficients from a list provided and (iv) application of these coefficients as boundary conditions in thermomechanical finite element simulations. An experimental procedure is established for the determination of the thermal time constant, the first step of the proposed methodology. Based on conduction, the proposed method provides a physically sound solution to heat transfer issues encountered in the modeling of thermal microactuators.

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Section: Review Of Modeling Approachesmentioning

confidence: 99%

On heat transfer at microscale with implications for microactuator design

Ozsun¹,

Alaca²,

Yalçınkaya³

et al. 2009

J. Micromech. Microeng.

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show abstract

“…Research efforts on thermal accelerometers have traditionally been initiated, justified and supported due to the potential for better reliability (there are no movable parts), better integration (fully compatible with IC fabrication processes) and stability [1][2][3]. Convective micro thermal-accelerometers were introduced in the 90's as an alternative to proof mass-based mechanical accelerometers and despite the claimed advantages, the success of these devices has been hampered by the relatively high power consumption (high thermal losses) and the difficulty to fabricate monolithically integrated 3-axis accelerometers.…”

Section: Introductionmentioning

confidence: 99%

Design of a 3-axis thermal accelerometer using an electro-thermo-fluidic model

Rocha¹,

Silva²,

Pontes³

et al. 2012

2012 13th International Thermal, Mechanical and Multi-Physics Simulation and Experiments in Microelectronics and Microsystems

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A three dimensional electro-thermal-fluidic FEM model is introduced in this paper and simulation results are used to design and predict the performance of a polymer based 3-axis thermal accelerometer. The model uses a sequential approach where initially the electro thermal model is simulated and the resulting temperature profile is used as input for a CFD simulation. Simulation results show that the required power to operate the sensor increases with the cross section of the heater and sensor sensitivity depends on the maximum temperature of the heater. Simulations using present sensor geometry show a sensitivity of 0.7°C/g in the X-Y directions and 0.3°C/g in the Z direction for a central heater temperature around 300°C.

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“…Nevertheless, the existence of the solid proof mass in the accelerometers brings some disadvantages, such as low shock survival rating and a complex fabrication process. Thermal accelerometer is a good alternative to solve the former problem since it works on thermal convection with no moving parts, except the gas used and contained in the micromachined cavity [2][3][4][5]. Figure 1 shows the principles of the sensor principle and a brief description of this is described here.…”

Section: Open Accessmentioning

confidence: 99%

Effect of the Detector Width and Gas Pressure on the Frequency Response of a Micromachined Thermal Accelerometer

et al. 2011

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Abstract:In the present work, the design and the environmental conditions of a micromachined thermal accelerometer, based on convection effect, are discussed and studied in order to understand the behavior of the frequency response evolution of the sensor. It has been theoretically and experimentally studied with different detector widths, pressure and gas nature. Although this type of sensor has already been intensively examined, little information concerning the frequency response modeling is currently available and very few experimental results about the frequency response are reported in the literature. In some particular conditions, our measurements show a cut-off frequency at −3 dB greater than 200 Hz. By using simple cylindrical and planar models of the thermal accelerometer and an equivalent electrical circuit, a good agreement with the experimental results has been demonstrated.

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Micromachined convective accelerometers in standard integrated circuits technology

Cited by 73 publications

References 3 publications

On heat transfer at microscale with implications for microactuator design

On heat transfer at microscale with implications for microactuator design

Design of a 3-axis thermal accelerometer using an electro-thermo-fluidic model

Effect of the Detector Width and Gas Pressure on the Frequency Response of a Micromachined Thermal Accelerometer

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