GaN power switches on the rise: Demonstrated benefits and unrealized potentials

As a wide bandgap semiconductor with high breakdown field, GaN is expected to outperform the incumbent Si technology for power switching applications. Advances in GaN epitaxial growth, device technology, and circuit implementations have resulted in high-performing power switches based on the GaN high electron mobility transistor (HEMT) structure. Demonstrated system benefits have validated the real value of GaN power switching technology. However, the full potential of GaN power switching technology is still far from being exploited. Various factors, including the size of electrodes and wiring, non-optimal E-field shaping, and substrate capacitive coupling, are limiting the performance of GaN HEMT power switches. Emerging device structures, such as, vertical transistors and multichannel superjunction transistors, have the potential to overcome some of those limitations, thereby bringing the performance benefits of the GaN power switching technology to a new level. Understanding the underlying physics is important to the success of the emerging device structures.