Gallium Nitride-Based HEMT Devices Modeling and Performance Characterization

88 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2008.The AlGaN/GaN high electron mobility transistor (HEMT) is a promising candidate for microwave applications due to its high power and low noise characteristics at such frequencies. As a result of improved material growth and processing technologies, microwave power densities have been demonstrated in AlGaN/GaN HEMTs that are five to ten times greater than that of corresponding GaAs-based devices. These higher power densities will result in simplifying the design and fabrication of monolithic microwave integrated circuits (MMICs). Power AlGaN/GaN MMIC design requires large signal modeling of the device. In bottom-up modeling techniques, the large signal model is based on small signal models derived at different bias conditions. In addition, noise performance analyses also require the knowledge of the small signal model in order to extract the intrinsic noise parameters. In this work, a new small signal equivalent circuit model extraction procedure is presented. The device noise model is developed based on this small signal model. Although AlGaN/GaN HEMTs show excellent properties in power and noise applications, they are still not widely adopted in commercial applications due to the reliability issue. The trapping effect is studied in our work by electrical and thermal methods.U of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD