SUMMARY

Research and development of wide bandgap semiconductors has showed that there is an amazing potential to affect the lives of everyday people. Improvements in widely available products like cell phones and light sources will be realized with the introduction of higher performance and more efficient devices. It is no surprise that the huge potential market has made wide bandgap semiconductors, specifically gallium nitride (GaN) the second most researched semiconductor. However there are still technical challenges that need to be addressed and overcome. It is the objective of this work to focus on heat dissipation in gallium nitride based solid-state logic devices as well as optoelectronic devices, a major technical challenge. Increases in device performance with improved materials have now been associated with an increase in power dissipation (>1kW/cm2) that is limiting further development. Determining material parameters will aid in the development of more representative models of device behavior that will allow for higher reliabilities to be demonstrated. Characterization of semiconducting thin films (as well as related substrates) is a non-trivial task due to the low dimensionality of heterostructure layers and often very high material thermal conductivity. To investigate the thermal conductivity, experiments were performed using the 3-omega method within a cryostat in order to find trends as a function of temperature. In addition to determining the thermal conductivity of various III-V semiconductors, temperature mapping was performed to study the heat flow within a device. Both micro infrared imaging and Raman spectroscopy were utilized in order to probe a high electron mobility transistor and a dual multi-quantum well LED. Comparisons were made between experimental results and device level-finite element modeling which provided the building blocks needed to perform a study of electronic packaging technologies.