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Thermal conductivity measurement by the 3omega method

Author: Bourlon, A.B. · Van der Tempel, L.
Type:report
Date:2006-01-24
Publisher: Philips Research
Institution: Philips Research
Identifier: tn2005-01035
Keywords: thermal conductivity measurement
Rights: (c) Koninklijke Philips Electronics N.V.

Abstract

ABSTRACT: The power of LEDs increases exponentially over the years,while the mean time to failure (MTTF) should remain >100000 hours. The reliability requirement limits the junction temperature and the thermo elastic stresses, which are roughly inversely proportional tothe thermal conductivity of the heat spreaders. The 3omega method has been set up to measure dynamically the thermal conductivity of anisotropic thin layers preferably in situ. CONCLUSIONS: The 3omega method measurement set up is operational from 10 Hz to 10 kHz The measured thermal conductivity of silicium deviates 50%, so the set upneeds to be improved. The length of the heater has already been checked. The goodness of fit of the sensor/heater calibration R² = 0.99998 The goodness of fit of the 3omega slope method R² = 0.99

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