| The ongoing trend of miniaturization on the nanoscale has created many new thermal challenges for device engineers and scientists. In many solid state devices, increased power densities in combination with continued size reduction is giving rise to thermal processes that can not be predicted by traditional macroscopic laws and models. For example, as transistor gate lengths are continuously decreasing in an effort to uphold Moore's Law, power dissipation is becoming a growing concern. As transistors shrink to length scales on the order of carrier mean free paths, the interfaces between solid materials in transistors and packaging systems are responsible for the major thermal resistances that are impeding power dissipation. An understanding of processes that contribute to thermal boundary conductance (hBD) continues to be a major research effort in nanoelectronic system design and engineering.; The goal of this study is to examine the scattering processes that contribute to thermal boundary conductance at metal-dielectric interfaces. These processes are examined through the transient thermoreflectance (TTR) technique. The TTR technique is a pump-probe measurement technique that employs ultrashort pulsed laser pulses (∼150 fs) to observe a temporal reflectance change on the surface of a material which in turn can be related to the transient temperature change to determine thermal properties. The TTR technique is used to observe the dependency of phonon transport on degrees of structural disorder at Cr/Si interfaces, the effects of elastic and inelastic phonon scattering at various metal/semiconductor interfaces, and the role of electron-interface scattering in electron-phonon equilibration during nonequilibrium heating in thin Au films. |
