Transient Response of Thin Film SiGe Micro Coolers

There are many applications where micro coolers are needed. Telecommunications lasers require a high degree of temperature control because their wavelength and power output are very temperature sensitive. Infrared detectors also need cooling because they have a much greater sensitivity at lower temperatures. One of the main factors that limits speed and miniaturization of very large scale integration VLSI circuits is their heat dissipation. Currently, conventional thermoelectric TE devices are used in many of these applications. Several features of thin film SiGe micro coolers give them an advantage over conventional bismuth telluride-based TE coolers in optoelectronic and electronic applications. They are better suited for applications where the needed cooling area is small and cost and reliability are important factors. The transient response of thin film SiGe micro coolers is measured using a thremoreflectance technique. Response time on the order of 20-40 s is obtained. The effect of device size and substrate thickness was investigated.