Gan-based electronics: material and device issues

Key issues related to the material structure and device processing of AlGaN/GaN HEMTs for applications in high-frequency and high-power electronics are discussed. Simultaneously results on selected issues like highly resistive GaN birffers, AlGaN/GaN 2DEG structures, low-resistive ohniic contacts and efJicierzt Schottky barrier contacts, as well as photoelectrocheniical wet etching of GaN are presented. Finally, preparation and properties of the AlGaN/GaN RoundHEMT, which is a simple device suitable for fast material structure characterization, are presented.