Okay I foung a first answer to my question in an interview with P. Copetti - but I will be happy about any further input about Gallium nitride!

MB: What’s different about your products vs. your competitors?

PC: To our knowledge, while there are efforts underway to develop a similar platform by other semiconductor companies, there is no one who has made significant progress towards a Moore’s Law solution.

Today, alternatives to silicon-based semiconductors are being developed to address the limitations of Moore’s Law. However, these solutions – which include different compounds such as silicon-germanium (SiGe), indium phosphide (InP) and gallium nitride (GaN) are based on high-cost hybrid manufacturing technologies. While there are also a few other alternatives in R&D mode, it’s still unknown when they will be available.

The POET platform, based in gallium arsenide, differs from other competing semiconductor processes as it is compatible with other semiconductor capabilities and manufacturing systems (which no other existing process can do) and removes the need for retooling, while providing lower costs, power savings and increased reliability.