0
RESEARCH PAPERS: Micro/Nanoscale Heat Transfer

Raman Thermometry of Polysilicon Microelectro-mechanical Systems in the Presence of an Evolving Stress

[+] Author and Article Information
Mark R. Abel

George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA 30332-0405

Samuel Graham1

George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA 30332-0405sgraham@me.gatech.edu

Justin R. Serrano, Sean P. Kearney, Leslie M. Phinney

Engineering Sciences Center, Sandia National Laboratories, Albuquerque, NM 87185-0834

1

Corresponding author.

J. Heat Transfer 129(3), 329-334 (May 31, 2006) (6 pages) doi:10.1115/1.2409996 History: Received January 17, 2006; Revised May 31, 2006

In this work, the use of Raman Stokes peak location and linewidth broadening methods were evaluated for thermometry applications of polysilicon microheaters subjected to evolving thermal stresses. Calibrations were performed using the temperature dependence of each spectral characteristic separately, and the uncertainty of each method quantified. It was determined that the Stokes linewidth was independent of stress variation allowing for temperature determination, irrespective of stress state. However, the linewidth method is subject to greater uncertainty than the Stokes shift determination. The uncertainties for each method are observed to decrease with decreasing temperature and increasing integration times. The techniques were applied to mechanically constrained electrically active polysilicon microheaters. Results revealed temperatures in excess of 500°C could be achieved in these devices. Using the peak location method resulted in an underprediction of temperature due to the development of a relative compressive thermal stress with increasing power dissipation.

FIGURES IN THIS ARTICLE
<>
Copyright © 2007 by American Society of Mechanical Engineers
Your Session has timed out. Please sign back in to continue.

References

Figures

Grahic Jump Location
Figure 1

Layout showing the sample used for temperature measurements in this study. The sample consists of a polysilicon microheater beam on a thick PECVD silicon dioxide on bulk silicon. Constraint in the movement of the microheater from the oxide layer is used to induce stress variations in the device.

Grahic Jump Location
Figure 2

Calibration of Stokes peak location for phosphorous doped polysilicon

Grahic Jump Location
Figure 3

Effect of stress on the linewidth of doped polysilicon (top). The scatter of the linewidth with stress is far less than the measurement uncertainty. The effect of stress on the Stokes peak location results in a linear shift with applied stress (bottom).

Grahic Jump Location
Figure 4

Linewidth calibration of phosphorous doped polysilicon which displays a quadratic behavior over the temperature range shown.

Grahic Jump Location
Figure 5

Estimated measurement uncertainty as a function of temperature from all sources. The uncertainty is based on a vector summation of the individual contribution to uncertainty and then taking 20 samples to reduce the single measurement uncertainty according to Eq. 3.

Grahic Jump Location
Figure 6

Temperature at the center of a microheater as a function of power dissipated. When comparing the Stokes and linewidth techniques, a thermally induced compressive stress was realized.

Grahic Jump Location
Figure 7

Temperature distribution of a fixed–fixed microheater using half-symmetry. A comparison of the Stokes and linewidth calibration is seen, revealing good agreement near the bond pad (distance=0◻m) and a significant difference at the beam center (distance=100◻m). The measured temperature difference (33°C) is greater than the ±15°C uncertainty between the two measurements at 400°C. This difference suggests the presence of a compressive stress in the device.

Tables

Errata

Discussions

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In