Thermometry of Polycrystalline Silicon Structures Using Raman Spectroscopy

Advances in Electronic Packaging, Parts A, B, and C ◽

10.1115/ipack2005-73088 ◽

2005 ◽

Cited By ~ 3

Author(s):

Mark R. Abel ◽

Samuel Graham

Keyword(s):

Raman Spectroscopy ◽

Intensity Ratio ◽

Thermal Stresses ◽

Stress Measurement ◽

Stokes Shift ◽

Temperature Measurements ◽

Raman Shift ◽

Ratio Method ◽

Mems Devices ◽

Anti Stokes

Raman spectroscopy was investigated as a method for the temperature and stress measurement in thermal MEMS devices. Calibrations of the Stokes Raman shift and the Stokes to anti-Stokes intensity ratio for doped samples were performed in order to calculate the temperature on simple polysilicon structures. Straight and serpentine micro-heaters of various sizes were fabricated from 2 micron doped polysilicon films on thick sacrificial oxide layers. Operating temperatures were measured at a range of input powers for devices attached to the oxide layer as well as released structures. Measurements show that all devices can exceed 400°C with the released devices requiring much less power, as expected. Temperature measurements using the Stokes shift method were compared to the conventional intensity ratio method in order to deduce the effects of thermal stresses on the temperature measurements. Using this method, it was found that thermal stresses could be qualitatively determined simultaneously with temperature in silicon MEMS devices. The effects of stress, however, results in less than a 10% difference in temperature over all of the input powers tested in this study.

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A Simple Calibration Method of Anti-Stokes–Stokes Raman Intensity Ratios Using the Water Spectrum for Intracellular Temperature Measurements

Applied Spectroscopy ◽

10.1177/0003702820933908 ◽

2020 ◽

Vol 74 (10) ◽

pp. 1295-1296

Author(s):

Yuki Yoshikawa ◽

Shinsuke Shigeto

Keyword(s):

Raman Spectrum ◽

Low Frequency ◽

Practical Method ◽

Calibration Method ◽

Temperature Measurements ◽

Raman Shift ◽

Acquisition Time ◽

Boltzmann Factor ◽

Intensity Ratios ◽

Anti Stokes

Presented here is a facile and practical method for calibrating anti-Stokes–Stokes intensity ratios in low-frequency Raman spectra that is devised specifically for temperature measurements inside cells. The proposed method uses as an intensity standard the low-frequency Raman spectrum of liquid water, a major molecular component of cells, whose temperature is independently measured with a thermocouple. Rather than calibrating pixel intensities themselves, we obtain a correction factor at each Raman shift in the 20–200 cm−1 region by dividing the anti-Stokes–Stokes intensity ratio calculated theoretically from the Boltzmann factor at the known temperature by that obtained experimentally. The validity of the correction curve so obtained is confirmed by measuring water at other temperatures. The anti-Stokes–Stokes intensity ratios that have been subjected to our calibration are well fitted with the Boltzmann factor within ∼1% errors and yield water temperatures in fairly good agreement with the thermocouple temperature (an average difference ∼1 ℃). The present method requires only 15 min of spectral acquisition time for calibration, which is 50 times shorter than that in a recently reported calibration method using the pure rotational Raman spectrum of N2. We envision that it will be an effective asset in Raman thermometry and its applications to cellular thermogenesis and thermoregulation.

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