Future of GaN RF Technology in Europe
In the last years GaN has remained a key technology in Europe in particular, but not only, for RF Applications. After an intensive period of research and development the scope has shifted towards industrialization and product development. This is especially true for the applications up to around 20GHz where systems are now being built using European GaN-based components. At the same time, an increasing part of the research activity has moved toward higher frequencies beyond 20GHz.
Manga: Manufacturable GaN
Manga is a five Nation (Germany, France, Italy, Sweden and United Kingdom) joint project realized by the European Defence Agency (EDA) which focuses on SiC substrates and a GaN epi wafers supply chain. The main objective of the project, started in March 2010, is to sustain the industrial development of semi-insulating silicon carbide substrates (SI SiC) and prove the industrial capability of Europe to deliver GaN HEMT and MMIC foundries with state-of-the-art GaN HEMT epitaxial wafers on SI-SiC substrates. This paper gives an overview on the current status of the technical developments achieved within the project.
Material and device issues of InAlN/GaN heterostructures
Motivation for replacing the AlGaN barrier layer of the conventional AlGaN/GaN HEMTs with lattice-matched InAlN is explained. State-of-the-art InAlN/GaN HEMTs are reviewed; emphasize is given to the analysis of the normally-off InAlN/GaN HEMTs using either a gate recessing or a concept of polarization engineering. Reliability issues of InAlN/GaN HEMTs are studied for different stress conditions and results discussed in respect to AlGaN/GaN HEMTs. Concept of InAlN/GaN/AlGaN double-heterostructure QW HEMT is shown to be more effective in blocking the hot electron injection in to the buffer. Novel InN-channel based devices are suggested with a relaxed InAlN buffer. The InN/InAlN-based HEMTs should be the choice for reaching a THz frequency range.