The Next Wave of GaN and SiC

Article By : Maurizio Di Paolo Emilio

At the recent PCIM Europe, several companies showed their latest innovations in GaN and SiC and offered insights on where WBG technology is headed.

Gallium nitride and silicon carbide are designated wide-bandgap (WBG) semiconductors based on the energy required to shift electrons in these materials from the valence to the conduction band — about 3.2 eV for SiC and 3.4 eV for GaN, compared with just 1.1 eV for silicon. The WBG properties lead to a higher applicable breakdown voltage, which can reach up to 1,700 V in some applications. At this year’s digital only PCIM Europe, held in May, several companies showed their latest innovations in GaN and SiC and offered insights on where WBG technology is headed.

The GaN power-device market doubled in 2020, highlighting the impressive growth of smartphone fast chargers and hinting at what’s to come in telecom and automotive markets, according to Yole Développement. Yole expects the GaN consumer power supply market to be the main driver, representing more than 60% of the market in 2026. The total GaN device market is forecast to grow from US$46 million in 2020 to about US$1.1 billion in 2026, with a CAGR of 70%.

During the PCIM event, EPC highlighted its GaN technology for time-of-flight/LiDAR systems targeting an increasing array of applications, from drones to robotics to autonomous vehicles and even vacuum cleaners. Nexperia, meanwhile, has announced its latest second-generation GaN technology. Yole asserted that, in the long term, in cases where GaN has proven its reliability and high-current capabilities at a lower price, the technology could penetrate the more challenging EV/HEV inverter market and the conservative industrial market, which could create remarkable volume opportunities for GaN. In fact, Nexperia and VisIC are working on GaN solutions that are intended to compete with SiC and silicon in xEV inverters.

New SiC designs are also emerging to meet growing high-power requirements for electric vehicles. SiC remains considerably more expensive than silicon, however, and silicon technology also continues to advance, with three-level and other silicon circuit topologies emerging to improve efficiency. Therefore, it’s important to identify applications in which the energy savings or other technical advantages achievable with SiC are sufficient to justify the cost. The economics might sometimes work in silicon’s favor.

Marc Rommerswinkel, principal client engagement manager at Microchip, said during the PCIM conference that he has no doubt about the advantages of SiC compared with Si-based solutions. Those include higher efficiency due to lower switching losses, as well as lower system size, cost, and weight because of higher switching frequencies and smaller cooling systems. However, “silicon carbide can be switched very fast, and any parasitic inductance can cause problems because of ringing and, with that, overshoots and undershoots, which cause EMC issues and can damage your system,” said Rommerswinkel. “This is something you need to consider if you use silicon carbide: Reliability and data such as the behavior of the subthreshold, the avalanche capability, or the body diode stability are only some parameters to consider.

”SiC devices have benchmark switching performance of much higher frequencies than silicon and virtually no reverse recovery. Furthermore, this superior and stable switching performance is independent of temperature. SiC’s ability to withstand higher operating voltage, current, and switching frequency — together with its high efficiency and excellent thermal management — makes this semiconductor the ideal replacement for silicon in several power applications, including automotive. Used in EV traction inverters, SiC is confirmed to support longer range and more efficient drive-cycle performance.

The price/performance trends for different material device types are continually evolving. Therefore, a standardized power loss evaluation tool that considers all types of devices from across the market is necessary for hardware engineers to make the best decisions.

This article was originally published on EE Times Europe.

Maurizio Di Paolo Emilio holds a Ph.D. in Physics and is a telecommunication engineer and journalist. He has worked on various international projects in the field of gravitational wave research. He collaborates with research institutions to design data acquisition and control systems for space applications. He is the author of several books published by Springer, as well as numerous scientific and technical publications on electronics design.

 

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