AspenCore’s PowerUP Expo 2021 devoted a full day to wide-bandgap (WBG) semiconductors, specifically gallium nitride (GaN) and silicon carbide (SiC). The WBG panel discussion focused on “the next wave of GaN and SiC,” taking its cue from the day’s topic presentations, including new product developments, technology challenges, and wafer manufacturing.
Thanks to their savings in size, weight, and cost, as well as higher efficiency, GaN and SiC power devices are making big pushes beyond fast chargers and renewable energy into data centers, motor drivers, electric vehicles (EVs), and other e-mobility applications.
The panel was comprised of six industry experts. Panelists in the GaN market included Alex Lidow, CEO and co-founder of EPC, who discussed GaN integration technology; Stephen Olivier, vice president of corporate marketing and investor relations at Navitas Semiconductor, who examined GaN’s role in electrification; and Caroline O’Brien, CEO of Kubos Semiconductor, who highlighted the company’s cubic-GaN technology for LEDs.
SiC panelists included Pete Losee, director of technology development at UnitedSiC (recently acquired by Qorvo), who discussed his company’s expanding portfolio with 750-V Gen 4 product series; Paul Kierstead, global director of power product marketing at Wolfspeed, who covered SiC’s role in renewable energy power conversion and storage; and Rob Rhoades, president and CTO of X-trinisic, who provided deep insight into SiC wafer manufacturing.
Common themes among the panelists included efficiency and integration, along with reducing the world’s reliance on fossil fuels with the help of WBG semiconductors. Panelists also agreed that the move to 200-mm wafers, coming soon, will be a further cost savings.
GaN: efficiency and carbon savings
Kubos’s O’Brien kicked off the panel with an introduction to the company’s new material technology, cubic GaN for LEDs. The next generation in lighting innovations is assumed to be the existing LED technology, but she counters that Kubos’s cubic-GaN LED technology could deliver a further 20% to 40% increase in efficiency. This translates into a carbon footprint and carbon savings of nearly 700 million tons of CO2 emissions over five years in lighting and displays, she said.
O’Brien said the new cubic-GaN can eliminate the inefficiencies in green and amber lights and offer opportunities in producing solutions that can be not only more efficient but also would improve color rendering and mimic daylight more effectively.
The “green gap,” or drop in efficiency in green and amber LEDs, is said to reduce the performance and increase the cost and size of RGBs. With cubic-GaN technology, the quantum confined stark effect and electric fields are eliminated, providing benefits in scale and longer wavelengths, and it delivers a reduced spectral drift, she said.
Similarly, GaN power device manufacturers like Navitas are focused on delivering technologies and devices that support electrification, which, in turn, reduce the world’s reliance on fossil fuels.
“Today, over 80% of the energy that becomes electricity is based on fossil fuels,” said Navitas’s Olivier. “One of the ways that we can improve that and shift from 20% renewables and electrical loads to 80% is by using GaN, which is a big push toward the electrification of our world.
“When we look at the small size of a GaN component and how we can integrate features and functions and reduce components from legacy systems, we can have up to a 10× smaller CO2 footprint than a silicon equivalent,” he said.
“Every time we ship a GaN power IC, we reduce 4 kg of CO2. That’s a huge net benefit by using new technology. We believe that we can accelerate the transition from internal-combustion-engine cars to EVs by three years worldwide and reduce road sector emissions by 20%, in all addressing a 2.6-gigaton-per-year reduction by 2050.”
GaN power device manufacturers agree that the move from discrete GaN to higher integration will drive increased efficiency. Both Navitas and EPC discussed their integrated GaN products that deliver on improved efficiency, smaller size, and greater power output.
One example is Navitas’s GaNFast power IC with an integrated gate drive with GaNSense technology that integrates autonomous sensing and protection circuits.
The beauty of GaN is the integration of high-voltage, high-power, low-voltage, digital-logic, and other devices on the same chip, said Lidow. “The advantage of GaN is that it is extremely fast, and if you put a driver right on the same chip as the power device, you can get much higher speed than if they’re in two different chips. You also get advantages in terms of power efficiency.”
A few years ago, EPC introduced its fully monolithic power stage, which delivered much greater efficiency and greater power output. It also translated into a smaller size, fewer components, and less design time.
EPC expects to take the technology to a higher level of integration, and by the 2023/2024 timeframe, discrete power devices will start to fade out of EPC’s toolbox in favor of devices that have integrated functions on board, said Lidow. “For GaN, it’s about integration going forward.”