Abstract

Wide band-gap semiconductors, such as GaN have shown promising characteristics for use in the future power electronic applications. Compared to the mainstream Si technology, GaN-based devices can function at higher temperatures, offer higher breakdown voltages up to 500 times higher than Si, and have lower on-resistance,approximately 10 times lower than the respective value in a Si switch. In this thesis, improved device figure of merit (FOM) RonQsw resulted from GaN’s fast switching speed and low on-resistance is utilized to enhance the power conversion FOM: Efficiency density/cost. To prove this idea, two half-bridge DC-DC converters with the same ratings and elements using GaN and Si switches are designed and the superior performance of GaN-based converter in terms of efficiency and size is confirmed through simulation and experiment. Simulation is based on the Spice models of commercial GaN and Si switches. Finally, design of GaN-based high electron mobility transistor for power applications is reported. According to the literature review and analytical calculations expected values in terms of switch breakdown voltage, on-resistance, and current capacity are predicted, followed by designing a mask set according to a typical fabrication process of AlGaN/GaN HFET.