We report the thickness and phase dependent thermal properties of Ge 2 Sb 2 Te 5 (GST) films using electrical Joule heating thermometry (3ω method) and validate the data with optical thermometry. The intrinsic thermal conductivity of GST increases from 0.26 W/mK for the amorphous phase to 0.57 W/mK for the crystalline phase. The thermal boundary resistance between GST and Si 3 N 4 films decreases from 134×10 -9 m 2 KW -1 to 25×10 -9 m 2 KW -1 after the phase change. The effective thermal resistance of GST shows a nonlinear dependence on the film thickness that infers the presence of microstructural defects. We separate the contributions of defects from intrinsic thermal transport and summarize possible causes for their thickness dependent behavior. An electrothermal simulation of PCM cell estimates the potential impact of the measured properties. This work improves the quality of PCM simulations by offering detailed knowledge of the distribution of thermal resistances.

There have been unprecedented temperature nonuniformities reported in conventional 2D-and emerging 3D-packaged multi-core microprocessors. Therefore, techniques for spatially resolving chip power and temperature profiles in fully operational chips are needed to improve circuit design and enable optimal cooling solutions. This paper presents a high-resolution, infrared (IR) thermography technique for microprocessors operating at fully-operational power levels. A custom, microfluidic heat sink with an IR-transparent working fluid (0.75 LPM) is manufactured to cool an instrumented test chip while permitting optical access for IR thermal imaging. A detailed system calibration is conducted to account for the temperature-dependent optical properties of the chip and heat sink. It is concluded that the IR imaging can be conducted with ~ 0.1 °C error over the temperature range of 45-90 °C if the fluid plenum height is less than 500 μm. For a 2 mm channel, the error can be as high as 43°C due to strong signal attenuation in the fluid.

No abstract