Gülseren, Melisa Ekin2019-08-022019-08-022019-072019-072019-07-30http://hdl.handle.net/11693/52291Cataloged from PDF version of article.Thesis (M.S.) : Bilkent University, Department of Electrical and Electronics Engineering, İhsan Doğramacı Bilkent University, 2019.Includes bibliographical references (leaves 110-115).GaN-based high-electron-mobility transistors (HEMTs) have been developing rapidly from the time when they were first demonstrated in the 1990s. They have consistently been presented as a displacement technology to silicon based power devices owing to the superior material properties of GaN such as high-electric breakdown field, high-electron saturation velocity, and high mobility. Normally-off GaN HEMT devices are particularly significant in power electronics applications. In this thesis, a comprehensive study of normally-off high-electron-mobility transistors is presented, including theoretical background review, theoretical analysis, physically-based device simulations, device fabrication and optimization and electrical characterization. p-GaN gate InAlN/GaN HEMT and recessed AlGaN/GaN MISHEMT devices have been successfully demonstrated.xvii, 115 leaves : illustrations (some color), charts ; 30 cm.Englishinfo:eu-repo/semantics/openAccessHEMTGaNInAlNNormally-offPower electronicsThreshold voltageAtomic layer depositionAluminaRecess etchFluorine treatementp-GaNThesisB160105