Is GaN-on-Si disruptive technology?
The mass adoption of GaN on Si technology for LED applications remains uncertain. Opinions regarding the chance of success for LED-On-Si vary widely in the LED industry from unconditional enthusiasm to unjustified skepticism. Although significant improvements have been achieved, there are still some technology hurdles (such as performance, yields, CMOS compatibility, etc.).
The differential in substrate cost itself is not enough to justify the transition to GaN on Si technology. The main driver lies in the ability to manufacture in existing, depreciated CMOS fabs in 6” or 8”. For Yole Développement, if technology hurdles are cleared, GaN-on-Si LEDs will be adopted by some LED makers, but it will not become an industry standard.
Yole is more optimistic about the adoption of GaN on Si technology for power GaN devices. Contrary to LED industry, where GaN on Sapphire technology is the main stream and presents a challenging target, GaN on Si will dominate the GaN based power electronics applications. Although the GaN based devices remain more expensive than Si based devices, the overall cost of GaN device for some applications are expected to be lower three years from now according to some manufacturers.
In 2020, GaN could reach more than 7 percent of the overall power device market and GaN on Si will capture more than 1.5 percent of the overall power substrate volume, representing more than 50 percent of the overall GaN on Si wafer volume, subjecting to the hypothesis that the 600 V devices would take off in 2014-2015.
GaN targets a $15 billion served available device market. GaN can power 4 families of devices and related applications. These are blue and green laser diodes, LEDs, power electronics and RF (see image).
Regarding GaN-on-Si LED, there will be no more than 5 percent penetration by 2020. As for GaN-on-GaN, it will be less than 2 percent. Yole considers that the leading proponents of LED-On-Si will successful and eventually adopt Si for all their manufacturing. Those include Bridgelux/Toshiba, Lattice Power, TSMC and Samsung. It expects that Silicon will capture 4.4 percent of LED manufacturing by 2020.
GaN wafer could break through the $2000 per 4” wafer barrier by 2017 or 2018, enabling limited adoption in applications that require high lumen output other small surfaces.