It's effectively process technology improvements that allow gallium nitride devices to become less defect prone. It's been known for some time that GaN has a s

It's effectively process technology improvements that allow gallium nitride devices to become less defect prone. It's been known for some time that GaN has a superior electron mobility number (which, effectively means you can get a better/smaller/lower impedance/faster switching device depending on which tradeoff you want). Problem is, getting reasonably good process control has been challenging. It appears some folks in the industry have been overcoming that challenge, therefore we're seeing the results of that.