Microscale heat conduction in integrated circuits and their constituent films

Advances in the semiconductor technology have enabled steady, exponential improvement in the performance of integrated circuits. Miniaturization allows the integration of a larger number of transistors with enhanced switching speed. Novel transistor structures and passivation materials diminish circuit delay by minimizing parasitic electrical capacitance. These advances, however, pose several challenges for the thermal engineering of integrated circuits. The low thermal conductivities of passivation layers result in large temperature rises and temperature gradient magnitudes, which degrade electrical characteristics of transistors and reduce lifetimes of interconnects. As dimensions of transistors and interconnects decrease, the resulting changes in current density and thermal capacitance make these elements more susceptible to failure during brief electrical overstress.; This work develops a set of high-resolution measurement techniques which determine temperature fields in transistors and interconnects, as well as the thermal properties of their constituent films. At the heart of these techniques is the thermoreflectance thermometry method, which is based on the temperature dependence of the reflectance of metals. Spatial resolution near 300 nm and temporal resolution near 10 ns are demonstrated by capturing transient temperature distributions in interconnects and silicon-on-insulator (SOI) high-voltage transistors. Analyses of transient temperature data obtained from interconnect structures yield thermal conductivities and volumetric heat capacities of thin films.; The thermal transport property data provide deeper insight into the microscopic mechanisms of heat conduction in amorphous passivation layers and in crystalline semiconductors. The data for silicon-dioxide films deposited using various methods show that atomic scale structural order and impurities affect the thermal transport properties of amorphous materials. The in-plane thermal conductivities of single-crystalline silicon films with thickness down to 80 nm indicate that high-frequency phonons dominate heat conduction in silicon near room temperature and above.; The experimental techniques and data of the present study aid with the simulation of temperature fields in integrated circuits. The theoretical understanding achieved in this work also assists the analysis of non-local heat transfer in semiconductors and the development of new materials for passivation layers.