An Introduction to High-Frequency GaN-based High Electron Mobility Transistors
This tutorial will give an overview of the principles, design, and current status of GaN-based high electron mobility transistors (HEMTs). We will first discuss the fundamental principles of GaN-based HEMTs, and focus on the aspects that differentiate them from conventional Si-based transistors, such as piezoelectric and spontaneous polarization, high breakdown field, transport properties, bulk/surface trap effects, and heterostructure engineering. We will then discuss the design of high frequency AlGaN/GaN HEMTs, and discuss how the physical structure - heterostructure and layout design - impacts RF parameters such as breakdown voltage, cutoff frequency, power gain, current gain, power density, and linearity will be discussed. Finally, the tutorial will give an overview of state-of-art III-Nitride high frequency transistors, and novel device concepts such as back-barrier design, N-polar HEMTs, and high Al-composition channel devices.