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.
Phase formation during mechanical alloying in the Ti–Si system
Abstract Mechanical alloying of Ti–Si powder mixture or TiH 1.924 –Si powder mixture was performed by high-energy ball milling, in which the Ti to Si mole ratio was 1:2. The phase formations in both mixtures during milling were investigated by X-ray diffraction. Mechanical alloying a mixture of elemental powders led to the formation of TiSi 2 equilibrium compound, while when starting from Si + TiH 1.924 , a metastable phase was formed. The metastable phase completely transforms to TiSi 2 when the mechanically alloyed powder is annealed at temperatures above 800 °C. Two different pathways of phase transitions during mechanical alloying are attributed to the existence of hydrogen atoms, i.e., when starting from Si + TiH 1.924 compared to Si + Ti, the kinetics for the formation of the TiSi 2 intermetallic compound slows down. The kinetics related to the different phase transitions depending on the starting powder mixture are discussed.