The first commercially available GaN-based products were available in 2005/2006 by companies with a long experience with GaAs technology (e.g. Cree, Nitronex). In the following years several other companies also entered the market. Table 2.3 gives an overview of the major substrate suppliers and foundries. Most of the products are based on epitaxially grown material on SiC substrates, however, there are some on Silicon, which offers lower costs and good thermal conductivity. One of the companies, which developed a GaN on Si process technology, is Azzuro, however, the bulk of its production is targeted at LED applications. Only recently Azzuro started providing substrates for GaN power devices. Another company, offering GaN epitaxial layers grown on Si is Nitronex. It also produces RF power transistors. Only two companies offer MMICs based on GaN: one of them is Cree which has developed traveling wave amplifiers, two-stage amplifiers, and high efficiency, high gain devices for radio communications. It uses SiC substrates. The other company to offer power amplifiers is Toshiba. It introduced its first GaN-based amplifier in 2008. Nowadays amplifiers delivering 50 W in the Ku-band are commercially available.
|Azzuro||GaN on Si||LEDs|
|Cree||GaN on SiC||220 W@4 GHz RF devices, MMICs|
|Eudyna||-||up to 3 GHz RF devices|
|Freescale||GaN on SiC||GaN-based HEMTs in research|
|Fujitsu||GaN on SiC||wireless equipment based on GaN HEMTs|
|Group4Labs||GaN on Diamond||-|
|Nitronex||GaN on Si||up to 6 W@6 GHz RF devices|
|Picogiga||GaN on SiC||-|
|RFMD||-||up to 120 W power devices|
|Triquint||-||up to 25W power devices|
|Toshiba||-||65.4 W@14.5 GHz RF devices|
One of the early players was Eudyna, which was a joint-venture of Fujitsu and Sumitomo Electric until 2009, before it was bought back by the latter. It offers both general purpose and high efficiency, high-gain devices for 3G/LTE applications with an operational voltage of 50 V.
Freescale produces GaN epi layers on SiC substrate and is currently researching HEMTs, however, no commercial products are available yet. Another company, which is driving the research in this field is Fujitsu. While it already offers GaN-based products, it also plans to deliver the first power supply products employing enhancement-mode GaN HEMTs in 2011.
Several companies focus solely on epi structure fabrication (Group4Labs, IQE, Picogiga). While most of them use a substrate SiC wafer, Group4Labs has developed a technology to attach GaN epi layers to diamond substrates and is researching HEMTs based on this approach.