Analytical modeling of spreading resistance in flux tubes, half spaces, and compound disks

A review of previously published models and solutions pertinent to the issue of modeling thermal resistances of diamond on copper heat sink systems is presented. The many particular solutions are shown to be special cases of the comprehensive model developed for a circular heat source in perfect thermal contact with the top surface of a compound disk which consists of two isotropic layers in perfect thermal contact. The bottom surface of the compound disk is subjected to a convective or contact cooling condition. Whenever possible simple models and correlation equations are presented for ease of computation. Bounds are presented for estimating the overall thermal resistance of several important cases