A silicon micromachined scanning thermal profiler with integrated elements for sensing and actuation

Gianchandani, Yogesh B.; Najafi, K.

doi:10.1109/16.641353

Cited by 29 publications

(15 citation statements)

References 43 publications

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“…The resistive heater located at the base of each probe permits in-situ testing of the TCs [10]. The TC output is monitored while the junction near the probe tip is held at room temperature and the junction at the base is heated by the resistor.…”

Section: Measurement Resultsmentioning

confidence: 99%

“…Its lower limit, which is relevant only in contact mode, is constrained by the effective contact and spreading (thermal) resistance at the probe tip. In noncontact mode, it can be shown that for a given R , the temperature drop along the probe length is highest when R R [10]. Since R generally exceeds 10 kW and varies with operating conditions, the design guideline is to maximize R .…”

Section: Structure and Operationmentioning

confidence: 99%

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Surface micromachined polyimide scanning thermocouple probes

Gianchandani

2001

J. Microelectromech. Syst.

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Abstract-This paper describes micromachined scanning thermocouple probes that exploit the low thermal conductivity and the high mechanical flexibility of polyimide as a structural material. They are surface micromachined using a low-temperature six-mask process suitable for appending to a CMOS fabrication sequence. The probes are 200-1000-m long, 40-120-m wide, and of varying thickness. They are assembled by a flip-over approach that eliminates the need for dissolving the substrate wafer or removing the probe from it. Temperature sensing is provided by thin-film Ni/W or chromel/alumel thermopiles embedded in the polyimide, which provide Seebeck coefficients of 22.5 and 37.5 V/K per junction, respectively. Modeling results indicate that the low thermal conductivity of polyimide, causes the temperature drop along the probe length to be much higher than with other candidate materials such as Si or SiO 2 , which contributes to improved thermal isolation of the sample and higher temperature sensitivity of the probe. However, the response time of the probe is compromised, and the measured 3 dB bandwidth of the probes is 500 Hz. A sample scan is presented. [561]

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Section: Measurement Resultsmentioning

confidence: 99%

Section: Structure and Operationmentioning

confidence: 99%

Surface micromachined polyimide scanning thermocouple probes

Gianchandani

2001

J. Microelectromech. Syst.

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“…Electrical resistance thermometry was introduced in [21], using a Wollaston wire shaped like a cantilever, enabling simultaneous thermal and AFM imaging. A surface micromachined thermal probe with integrated 1D electrostatic actuation was reported in 1997 [22]. A CMOS thermal probe with integrated piezoresistive detection is described in [23].…”

Section: Scanning Probe Microscopymentioning

confidence: 99%

Single‐Chip Scanning Probe Microscopes

Sarkar

Mansour²

2015

Micro‐ and Nanomanipulation Tools

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Scanning probe microscopes (SPMs) are the highest resolution imaging instruments available today and are among the most important tools in nanoscience. Conventional SPMs suffer from several drawbacks owing to their large and bulky construction and to the use of piezoelectric materials. Large scanners have low resonant frequencies that limit their achievable imaging bandwidth and render them susceptible to disturbance from ambient vibrations. Array approaches have been used to alleviate the bandwidth bottleneck; however as arrays are scaled upwards, the scanning speed must decline to accommodate larger payloads. In addition, the long mechanical path from the tip to the sample contributes thermal drift. Furthermore, intrinsic properties of piezoelectric materials result in creep and hysteresis, which contribute to image distortion. The tip-sample interaction signals are often measured with optical configurations that require large free-space paths, are cumbersome to align, and add to the high cost of state-of-the-art SPM systems. These shortcomings have stifled the widespread adoption of SPMs by the nanometrology community. Tiny, inexpensive, fast, stable and independent SPMs that do not incur bandwidth penalties upon array scaling would therefore be most welcome. A method to increase the quality factor (Q-factor) of flexural resonators is introduced. The method relies on an internal energy pumping mechanism that is based on the interplay between electrical, iv mechanical, and thermal effects. To the best of the author's knowledge, the devices that are designed to harness these effects possess the highest electromechanical Qs reported for flexural resonators operating in air; electrically measured Q is enhanced from ~50 to ~50,000 in one exemplary device. A physical explanation for the underlying mechanism is proposed.The design, fabrication, imaging, and tip-based lithographic patterning with the first single-chip Scanning Thermal Microscopes (SThMs) are also presented. In addition to 3 DOF scanning, these devices possess integrated, thermally isolated temperature sensors to detect heat transfer in the tip-sample region.Imaging is reported with thermocouple-based devices and patterning is reported with resistive heater/sensors. An "isothermal electrothermal scanner" is designed and fabricated, and a method to operate it is detailed. The mechanism, based on electrothermal actuation, maintains a constant temperature in a central location while positioning a payload over a range of >35μm, thereby suppressing the deleterious thermal crosstalk effects that have thus far plagued thermally actuated devices with integrated sensors.

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“…Such a problem is frequently encountered in MEMS/NEMS devices as in, for example, the scanning thermal profiler [29][30][31]. Figure 4 illustrates the simulation model.…”

Section: B Fourier Thermal Problemmentioning

confidence: 99%

Performance evaluation of Maxwell and Cercignani-Lampis gas-wall interaction models in the modeling of thermally driven rarefied gas transport

Liang

2013

Phys. Rev. E

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CitationPerformance evaluation of Maxwell and CercignaniLampis gas-wall interaction models in the modeling of thermally driven rarefied gas transport 2013, 88 (1) Physical Review E A systematic study on the performance of two empirical gas-wall interaction models, the Maxwell model and the Cercignani-Lampis (CL) model, in the entire Knudsen range is conducted. The models are evaluated by examining the accuracy of key macroscopic quantities such as temperature, density, and pressure, in three benchmark thermal problems, namely the Fourier thermal problem, the Knudsen force problem, and the thermal transpiration problem. The reference solutions are obtained from a validated hybrid DSMC-MD algorithm developed in-house. It has been found that while both models predict temperature and density reasonably well in the Fourier thermal problem, the pressure profile obtained from Maxwell model exhibits a trend that opposes that from the reference solution. As a consequence, the Maxwell model is unable to predict the orientation change of the Knudsen force acting on a cold cylinder embedded in a hot cylindrical enclosure at a certain Knudsen number. In the simulation of the thermal transpiration coefficient, although all three models overestimate the coefficient, the coefficient obtained from CL model is the closest to the reference solution. The Maxwell model performs the worst. The cause of the overestimated coefficient is investigated and its link to the overly constrained correlation between the tangential momentum accommodation coefficient and the tangential energy accommodation coefficient inherent in the models is pointed out. Directions for further improvement of models are suggested.

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A silicon micromachined scanning thermal profiler with integrated elements for sensing and actuation

Cited by 29 publications

References 43 publications

Surface micromachined polyimide scanning thermocouple probes

Surface micromachined polyimide scanning thermocouple probes

Single‐Chip Scanning Probe Microscopes

Performance evaluation of Maxwell and Cercignani-Lampis gas-wall interaction models in the modeling of thermally driven rarefied gas transport

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