Progress in SiC and GaN microwave devices fabricated on semi-insulating 4H-SiC substrates

The two technologies being studied are SiC MESFETs based on homoepitaxially grown epilayers, primarily targeted for applications from UHF up to 10 GHz, and GaN/AlGaN HEMTs that are grown via heteroepitaxial MOCVD which can operate at frequencies potentially up to 35 GHz. As a result of the use of 4H-SiC semi-insulating substrates, impressive demonstrations of microwave power have been made in both types of devices. This paper will describe progress made in SiC substrates, and some of the resulting microwave device demonstrations in both SiC MESFETs and in GaN/AlGaN devices grown on SiC.