Here is the abstract you requested from the Thermal_2011 technical program page. This is the original abstract submitted by the author. Any changes to the technical content of the final manuscript published by IMAPS or the presentation that is given during the event is done by the author, not IMAPS.
|High-Speed Thermoreflectance Imaging for Thermoelectric Device and Semiconductor Material Characterisation|
|Keywords: thermoreflectance imaging, high-speed, material characterisation|
|Thermoreflectance imaging is a non-invasive technique to measure 2-D temperature maps of semiconductor devices and ICs. By using LED illumination in the visible wavelength range and megapixel CCD detection, thermal maps with submicron spatial resolution can be obtained without the need to scan the sample. Timing algorithms that phase-lock the imaging system to a DUT under pulse mode bias allow to capture the thermal transients with temporal resolution of 100ns or better. In this paper, we illustrate two applications to electrothermal device and semiconductor material characterisation. The first consists of the analysis of an integrated high-speed SiGe superlattice microrefrigerator. These devices were customly designed as test structure for study of ultrafast Peltier effects at the metal/superlattice interface. Thermal images taken in the 100-300ns range under a variety of bias currents indicate ultrafast active cooling response. They also reveal expected differences in the time constants and current dependence associated with the competing Peltier and Joule effects, while hot spots at the electrode neck suggest that the metalisation at the superlattice side wall be improved. For the second case study, we recently investigated high-speed Joule heating in coplanar waveguide heaters. A long metal line of a couple microns wide is deposited onto a substrate under study. Preliminary imaging results under 1us pulse width bias show that the spatial decay of the temperature field perpendicular to the line can be resolved, enabling to track how the heat gradually spreads into the substrate as time progresses. Comparison to a reference structure should provide the thermal diffusivity of the substrate. Since this characterisation is performed on fast transients with time constants far beyond the capabilities of 3-omega methods, this approach may also offer great potential in studying ballistic effects in semiconductor alloys.|
|Bjorn Vermeersch, Post-Doctoral Researcher
University of California, Santa Cruz
Santa Cruz, CA