Ultra-fast thermoreflectance imaging

Post date: Oct 15, 2009 6:11:22 AM

Watch our transient thermal imaging videos below:

Thermoreflectance thermal imaging is a noninvasive optical technique particularly suited for surface temperature mapping of active semiconductor devices. This method is sensitive to mK temperature fluctuations with nano-second temporal resolution and can produce 2D thermal images with submicron spatial resolution.

Thermoreflectance image (TRI) of a microscale thermoelectric cooler device. 

Seperation of Joule and Peltier components is possible with the TRI system.

Thermoreflectance is based upon the detection of a variance in sample surface reflectivity due to a change in surface temperature as shown in the figure below. The thermoreflectance coefficient defines this relationship and is influenced by sample composition, wavelength of probing light, and measurement apparatus.

Principle of the thermoreflectance imaging technique

With accurate control of time intervals between the pulsed device excitation and the LED illumination, ultra-fast transient thermal imaging can be achieved. the temporal resolution is determined by the LED pulse width, and a ~ 50 ns resolution or shorter is possible.

Transient thermoreflectance images of a 30 x 30 μm2 microcooler

For more information, see the references below:

• J.-H. Bahk and A. Shakouri, "Ultra-fast Thermoreflectance Imaging for Electronic, Optoelectronic, and Thermal Devices," IEEE Proc. BCICTS, Nashville, TN (2019). (Invited conference paper)

• J.-H. Bahk, T. Favaloro, and A. Shakouri, “Thin film thermoelectric characterization techniques,” Chap. 3, Annual Reviews of Heat Transfer vol.16, Ed. G. Chen (Begell House Inc., New York, 2013).

• B. Vermeersch, J.-H. Bahk, J. Christofferson, and A. Shakouri. “Thermoreflectance imaging of sub 100 ns pulsed cooling in high-speed thermoelectric microcoolers,” J. Appl. Phys. 113, 104502 (2013).

• Thermoreflectance Imaging System by Microsanj Inc. http://www.microsanj.com/