Thermal properties of novel electronic materials

The excellent interface quality with silicon dioxide and the ease of its doping, have made silicon the most prominent semiconducting material. However, improvements in electrical and thermal device performance may require use of different materials, either as supplements to the existing technology (e.g low-dielectric-constant passivation for interconnects) or as complete replacements of silicon in the active region for selected applications (e.g. GaAs or SiGe). Recent advances in combinatorial chemistry made possible fabrication of materials with pre-defined composition. Thermal conduction properties of these emerging materials will be important in predicting device performance. In some applications such as thermoelectric cooling and generation, radiation detection, or heat spreading in high-power devices, these properties directly influence associated figures of merit.; This thesis develops a systematic approach for the thermal characterization of emerging materials. Both experimental and analytical tools are developed for such characterization. An experimental technique employs flash laser heating and thermoreflectance thermometry, which uses the temperature dependence of the optical reflectivity to detect changes in the temperature of the sample surface. This technique is suited particularly well for studying thermal properties of novel films of thickness below one micrometer. The analytical tools developed here model phonon heat transport in polycrystalline and monocrystalline materials, based on the material microstructure and thermal conduction research for bulk materials. Data are reported for polycrystalline thin diamond layers and monocrystalline Bi₂Te₃/Sb₂Te₃ superlattice layers.; The experimental and analytical characterization tools developed in this study can be extended to study thermal properties of many novel materials. The high-throughput purely-optical technique is capable of measuring thermal conduction properties in the geometries appropriate for many electronic applications. The incorporation of new analytical techniques into simulation software can provide corrected values of thermal conductivity to aid with the accuracy of predicting device performance, given that the microstructure of the material is known or can be controlled.