Woodruff School of Mechanical Engineering



GaN electronics - Thermal Management, Reliability and Integration with Diamond


Prof. Martin Kuball


University of Bristol, UK


Wednesday, September 21, 2016 at 3:00:00 PM


MRDC Building, Room 4211


Dr. Samuel Graham


The development of GaN high electron mobility transistors is a promising technology for the advancement of future RF-communication systems. In compared to GaAs based material, GaN electronics have a larger breakdown field, higher carrier mobility, and large sheet charge density that allows for operation at high frequency and high power. Applications include both radar and cellular base-stations. However, the promise of GaN RF devices comes with challenges, specifically in managing the large heat fluxes (>1kW/cm2) and self-heating which occurs in these devices. Thus, advanced thermal management solutions are critical in the development of this technology in order to realize the full potential and reliability of GaN transistors. In a more recent approach, diamond films have been introduced into the device structure to reduce the junction temperature of high power GaN devices. However, the solution is not optimal and comes with challenges. In this talk, we will introduce some of the major challenges for cooling GaN devices and its impact on device reliability. Advanced state of the art techniques to characterize the electrical and thermal response of devices and materials will be presented. A key focus will be on the integration challenges of GaN with CVD diamond and methods needed to advance this thermal management strategy to realize the potential of high power GaN RF devices.


Martin Kuball is a Professor of Physics and the Director of the Center for Device Thermography and Reliability (CDTR) at the University of Bristol, UK. He is Fellow of IET and IoP, and holds a Royal Society Wolfson Merit Award. He has a PhD from the Max Planck Institute for Solid State Physics, Stuttgart, Germany, and was Feodor Lynen Fellow at Brown University prior to joining the University of Bristol.