Substrates for GaN devices: growing in more ways than one

Our new market on substrates for GaN-based devices is now available. Our take on that market? That's one market segment that's growing, and we don't mean growing just crystals. We forecast merchant substrate sales growing from $280 million in 2008 to $470 million in 2013. But, native GaN has a ways to go, and 6-inch substrates are a long way off.

The new report from our SU analysts Bob Steele and Hank Rodeen updates our earlier reports, addressing both the devices and the substrates used for shorter-wavelength LEDs, blue lasers, and widebandgap electronics. The substrates are mainly sapphire or SiC, with the GaN grown on top, although there are a number of variations and alternatives to get the GaN layer. The substrates have been mainly 2-in in diameter, but are quickly moving to 3- and 4-inch diameters.

The rapid migration stops there, however, in part because of the difficulty to work with GaN but also the manufacturing costs involved in the specific devices fabricated in GaN. In widebandgap electronics, for example, Cree points out that the substrate technology will be ready before the volumes will be. And the electronic devices are relatively large, but not large and pricey enough to merit the jump to larger substrates.

And as for bulk GaN substrates--well--they are simply too difficult to grow and expensive to use for the time being. Inexpensive bulk GaN would be ideal for devices based on GaN, but nature provides alternatives today that are good enough at a lot less cost, and still getting cheaper. Without that volume, bulk GaN remains perpetually behind, or at least far enough behind to be unimportant to our 5-year forecast.