Commercialization of High Voltage GaN

December 14, 2014 by Jeff Shepard

High Voltage GaN is redefining power conversion, providing cost-competitive and easy-to-embed solutions that reduce costly energy loss by more than 50%, shrink size and simplify the design and manufacturing of power supplies and adapters, PV inverters, motor drives and electric vehicles. Transphorm has established the next power conversion platform – demonstrating breakthrough performance and introducing the world's first 600 Volt GaN products with its EZ-GaN™ platform.

Generation-1 products have been JEDEC qualified since January 2013. Our customers demanded qualification to JEDEC standards as a key requirement for system insertion. While JEDEC was originally applicable to Silicon products, it is an equally important benchmark for GaN. It actually turns out that for higher activation energy semiconductors such as GaN, 1000 hours of accelerated testing is in fact much more stringent than 1000 hours of accelerated testing in Silicon (this will be discussed in detail in a future article in this series). Complementing our JEDEC qualification, we have now also demonstrated the first life-time results for any GaN power technology- a high voltage off-state lifetime (electric field accelerated lifetime) of more than 10 Million hours at 600V.

Providing distinct benefits of size (power density) and efficiency (energy loss) over Silicon superjunction MOSFETs and Silicon IGBTs, Transphorm high voltage GaN discrete and module products have been designed into various applications ranging from 4.5kW residential PV Inverters to kW class 99% efficient Totem Pole PFC circuits as well as into multi-hundred watt “All-in-One Computer” compact power supplies. While we continue to work on advanced packaging to harness the ultimate properties of GaN, it is worthwhile to note that existing packages like the TO220, TO247, and PQFN work well and are indeed providing significant value with high voltage GaN today, when coupled with the right topology (e.g. Transphorm Quiet Tab™) and circuit layout (to be discussed in detail in a future article in this series).

The fact that the PV Inverter was the first application to adopt GaN came as a surprise to most engineers and quality teams, because they assumed the 25 year life requirement would not be compatible with a new technology such as GaN. Instead they are now learning as we believed and are now confirming, that once the GaN products are designed to successfully pass qualification, the GaN chips are in fact extremely robust and capable of long life as our most recent testing has confirmed. Although passing the 1,000 hour HTRB testing was an important achievement, recent tests have shown that the same devices are capable of continuing well past 10,000 hours of accelerated high voltage and high temperature testing. Following the initial design wins in PV Inverters, other applications such as power supplies for servers and computers are following rapidly.

Transphorm’s access to high quality, high scale foundry manufacturing through its relationship with Fujitsu Semiconductor, enables it to meet growing demand from global customers needing energy-saving GaN products. A key effort for this year (2014) has been the successful transferred our 600V GaN process from the Goleta-CA pilot production fab to the Aizu-Wakamatsu high volume 6-inch foundry which began sampling earlier this year. The ability to rapidly transfer the process demonstrates both the maturity of the design and confirms that

Transphorm’s success in qualifying the 600V GaN was not a one-time accident. It further underlines its systematic, documented and transferrable knowhow in GaN high voltage epi, devices and fabrication areas. It is noteworthy that the Aizu foundry is automotive supply qualified, assuring strong quality along with commercial scale needed to supply our Japanese and world-wide customers.

Our products are backed by a broad and deep intellectual property portfolio, comprising more than 450 independent and more than 1100 world-wide patents/patent applications—the most extensive IP portfolio in the GaN Power arena. As the GaN Power market expands, and very similar to the history witnessed in the GaN LED market explosion in the late 90s/early 2000’s, companies with the strongest IP along with an ability to supply products to the market will dominate. Transphorm’s IP encompasses fundamental patents across the value chain, ranging from GaN on Si epi growth, GaN device design and fabrication, high speed/high frequency packages for GaN as well as patents for the utilization of GaN in the most promising circuit applications (e.g. bridge circuits).

For customers looking for a low-risk roadmap to the next generation of power conversion technology, EZ-GaNâ„¢ provides a cost-effective, customizable and easy-to-use solution ready for commercial scale.

written by: Primit Parikh, President and Co-Founder, Transphorm Inc.