| In this doctoral thesis, we focus on the experimental analysis and modeling of heat transport properties in micro to nano-scale, with an emphasis on the solid state electronics related applications. These viewpoints serve as a common ground for the five chapters in this manuscript, and structurally relate them with each other. Chapter I is introductory, where we discuss the general picture of heat transfer, from the fundamental meanings of heat and temperature to the novel transport phenomena due to the extreme size of modern materials. From chapter II to chapter V, we setup a particular scenario of heat transport in each. We aim to indentify the most fundamental problem in the particular scenario, provide precise physical description, and propose analysis approaches. In chapter II, we study phonon confinement and its influence on thermal conductivity in germanium nanowires with different cross-section diameters. In chapter III, we discuss the advantages and issues of thermal conductivity measurement of individual nanostructures using suspended micro-devices. The scope is moved from nano-scale passive material to micro-scale active devices in chapter IV. We obtained high resolution thermoreflectance images from individual MOSFET transistors and identify a strong bias condition dependence of local thermal resistance, as well as a bias condition dependence of hot spot dislocation when the gate width reaches the hundred nanometer regime. In chapter V, we view the picture of heat transport on IC chip level. A Green's function based fast modeling algorithm is used to predict the temperature distribution on the surface of an array of power transistors, with the consideration of non-uniform potential distribution. A summary of the overall findings of this doctoral thesis study, as well as a brief outlook session, is given at the end of this manuscript. |
