GaN-on-Si substrate for LED and power electronics

Yole Développement’s analysts both develop possible business models for the adoption of GaN-on-Si technology. GaN-on-Si substrate technology and market for LED and Power Electronics report also includes market volume and revenue forecast to 2020.

Today, GaN on Sapphire is the main stream technology for LED manufacturing. GaN-on-Si technology appeared naturally as an alternative to sapphire to reduce cost. Yole Développement’s cost simulation indicates that the differential in silicon substrate cost is not enough to justify the transition to GaN-on-Si technology. The main driver is the ability to manufacture in existing, depreciated CMOS fabs in 6 or 8”.

At Yole Développement, analysts believe that although significant improvements have been achieved, there are still some technology hurdles (performance, yields, CMOS compatibility). They consider that if the technology hurdles are cleared, GaN-on-Si LEDs will be adopted by some LED manufacturers, but will not become the industry standard. Yole Développement expects that Silicon will capture less than 5% of LED manufacturing by 2020.

“Despite potential cost benefits for LEDs, the mass adoption of GaN-on-Si technology for LED applications remains unclear. Opinions regarding the chance of success for LED-on-Si vary widely in the LED industry from unconditional enthusiasm to unjustified scepticism. Virtually all major LED makers are researching GaN-on-Si LED, but few have made it the core of their strategy and technology roadmap. Among the proponents, only Lattice Power, Plessey and Toshiba have moved to production and are offering commercial LED-on-Si”, explains Dr Hong Lin.

The power electronics market addresses applications such as AC/DC or DC/AC conversion, which is always associated with substantial energy losses that increase with higher power and operating frequencies. Incumbent silicon based technology is reaching its limit and it is difficult to meet higher requirements. GaN based power electronics have the potential to significantly improve efficiency at both high power and frequencies while reducing device complexity and weight. Power GaN are therefore emerging as a substitution to the silicon based technology. Today, Power GaN remains at its early stage and presents only a tiny part of power electronics market.

“We are quite optimistic about the adoption of GaN-on-Si technology for Power GaN devices. GaN-on-Si technology have brought to market the first GaN devices. Contrary to the LED industry, where GaN-on-Sapphire technology is main stream and presents a challenging target, GaN-on-Si will dominate the GaN based power electronics market because of its lower cost and CMOS compatibility”, says Dr Eric Virey. "Although GaN based devices remain more expensive than Si based devices today, the overall cost of GaN devices for some applications are expected to be lower than Si devices three years from now, according to some manufacturers. In our nominal case, GaN based devices could reach more than 7% of the overall power device market by 2020. GaN-on-Si wafers will capture more than 1.5% of the overall power substrate volume, representing more than 50% of the overall GaN-on-Si wafer volume, subjecting to the hypothesis that the 600V devices would take off in 2014-2015."

To adopt the GaN-on-Si technology, device makers have the choice between buying epiwafers or templates on the open market, or buying MOCVD reactors and making epiwafer by themselves. Today, there is a limited number of players selling either epiwafers or templates or both on the open market. These players comes from Japan, US and Europe. We have not observed an absolute dominance from one region.

As perceived by device markers, each business model has its pros & cons in terms of IP, technology dependence, R&D investments and time. According to Yole Développement’s reports, analysts do not expect to see a significant template/epiwafer business emerge for LEDs and consider that LEDs makers would prefer making their epiwafers internally for mass production. For the power electronics industry, the opinion is divided. Yole Développement considers that buying epiwafers could work as long as the price of the epiwafer on the open market keeps decreasing.