Novel Infra-Red (IR) Thermal Measurements on GaAs Micro-Coolers

Electronic devices are shrinking in size and new materials, for example gallium nitride (GaN) are being introduced, resulting in higher dissipated power densities. Therefore, new and novel technologies are required to remove the heat and to thermally characterise the devices. A particular example of a device that will require these thermal management technologies is the gallium arsenide (GaAs) planar Gunn diode [1] which is being developed for millimetre-wave and terahertz (THz) frequencies, and in which the dissipated power density will be very high (approximately 106 W/cm2 ). This paper will review preliminary thermal and electrical characterisation of a GaAs electro-thermal micro-cooler with the aim of its integration with the planar Gunn diodes, thus increasing the efficiency of the latter. The thermal characterisation of these electro-thermo coolers brings its own set of unique measurement problems. A comparative temperature measurement has been developed using infra-red (IR) thermal microscopy and novel micro-particle sensors [2]. The measurement technique will be described in detail and preliminary measurements on simple superlattice electro-thermal GaAs micro-coolers will be presented