(Invited) Characterization of Thermal Effects in Wide Bandgap Semiconductor Materials and Devices

Wide bandgap electronics made from nitrides (e.g., Gallium Nitride (GaN)) and oxides (e.g., Gallium Oxide (Ga2O3)) are currently under development due to their potential to create some of the most advanced RF and power electronic devices in the world. However, the thermal response of these devices under applied electric fields can create large power densities (RF and power electronics) that must be understood. For many of these devices, the electrothermal response plays a strong role in both the acceptable operation or long-term failure and reliability of the devices. Thus, tools that can help elucidate these responses and provide a method to help design better devices is of critical need for this field. In this talk we will discuss advancements in thermal characterization techniques that have allowed new insights into electrothermal behavior in GaN and Ga2O3 materials and devices. Specifically, a focus on the role of device architecture and material processing will be addressed. For GaN and Ga2O3 RF and power electronics, the role of thermal interfaces in the heat dissipation of both lateral and vertical device architectures will be discussed. We will cover aspects of semiconductor-semiconductor as well as metal-semiconductor interfaces and their roles in device thermal management. A highlight will be the use of plasma activated bonding to provide ultralow thermal resistance interfaces that allow for heterogenous integration of nitrides and oxides with high thermal conductivity substrates. Finally, we will discuss the implications of these effects on device behavior through experiments and modeling.