Physics Based Design and Development of Gallium Nitride High Electron Mobility Transistors HEMTs and Schottky Barrier Diodes for Power and RF Applications

Abstract

Silicon-based transistors such as MOSFETs have been the preferred choice for decades now for both power as well as high-frequency device applications. The meteoric rise of Silicon was fuelled by the quest for a highly efficient and low-cost switching device. However, the rate of performance improvement in Silicon-based devices is levelling off over the past few years due to underlying theoretical limits set by fundamental physics. It has become extremely challenging to deliver the performance standards at declining costs consistently. GaN has risen as the most promising alternative to traditional Silicon-based technology. The wide bandgap and ability to conduct carriers at very high mobility infuses a positive momentum to the Moor s law. The fundamental high electric field strength of the material ensures a significant reduction in device size for a given on-resistance and breakdown voltage. It directly translates to lower effective costs per chip. The existing commercial products with 5-10 times enhanced performance compared to Silicon theoretical limits is a strong motivation to further optimize GaN-based devices for power and RF applications. Silicon-based devices have long enjoyed the luxury of an established technology development process, which has been optimized over the years via several iterations and efforts. TCAD based design is the stepping-stone for any technology realization. Employing theoretical knowledge and visualizing the physics in real-time for device design or optimization is the heart of the Silicon Industry. The amount of design cost and time saved by following a consistent CAD design to fabrication approach is enormous. On the contrary, GaN-based devices have unique properties and associated design parameters. The conventional Silicon device design knowledge cannot be extrapolated to GaN-based devices. A wide gap exists between the theoretical and reported performance of GaN-based power and RF devices. A systematic design approach is needed, which involves both simulation and experimen...