Airbus, STMicroelectronics Collaborate on SiC/GaN Aircraft Electrification Initiatives

Airbus and STMicroelectronics will collaborate on research and development for lighter, smaller, more efficient power electronics solutions for future hybrid, all-electric and hydrogen-powered aircraft.  The partnership is congruent with Airbus’ goal of reducing aviation’s dependence on carbon fuels by developing alternative propulsion systems.  

 

ZEROe hybrid-hydrogen turbofan aircraft concept. Image used courtesy of Airbus

 

The research will focus on novel applications of advanced compound semiconductor materials like silicon carbide (SiC) and gallium nitride (GaN), which offer higher power densities than traditional silicon substrate devices. The result will be lighter, more efficient power conversion solutions suited to the needs of aircraft propulsion and other systems. 

The scope of the research will include discrete SiC and GaN devices, advanced packaging, and module integrations. The solutions will be researched and tested in demonstration platforms to evaluate their suitability for future aircraft production applications. 

 

Reducing Aviation’s Carbon Footprint

According to the U.S. Department of Energy (DOE), commercial aviation accounts for 10% of all transportation energy consumption and 2% of the nation’s carbon emissions.

Airbus, a leading global aircraft manufacturer, has committed to developing alternative aircraft propulsion systems based on hydrogen, electricity, and hybrid power sources to offer a viable, even superior, alternative to traditional, carbon-based aircraft fuels. 

Airbus’ ZEROe program is exploring several propulsion concepts using hydrogen as a combustion fuel and source of electricity via fuel cells for a highly efficient hybrid-electric propulsion system. 

CityAirbus NextGen is an all-electric, four-seat vertical take-off and landing (eVTOL) prototype targeted for emerging urban air mobility applications. According to Airbus, by 2030, 60% of the world’s population will live in urban centers. 

 

Reducing aviation’s carbon footprint. Image used courtesy of Airbus

 

The idea behind urban air mobility is to offer urban populations the opportunity to use the airspace above their city to meet their local transportation needs, similar to an air taxi or public bus service. Due to the short ranges, all-electric, battery-powered aircraft are well-suited to these use cases.   

To execute its initiatives, Airbus has developed a modular energy transformation roadmap set to impact all of the company’s aviation platforms.

The roadmap incorporates a range of technologies and initiatives to include the use of sustainable aviation fuels (SAF), hybrid-electric engine design (hydrogen combustion and fuel cells), and future full electric flight (fuel cells and batteries).

Light, small, and efficient power management and conversion solutions will be critical to Airbus’s hybrid and electric propulsion development roadmap, emphasizing the importance of the new R&D collaboration with power innovator STMicroelectronics.  

 

Compound Semiconductors for Electric Aircraft Propulsion

Airbus’ vision for future hybrid and all-electric aircraft will depend on the availability of exceptionally light and highly efficient power conversion solutions that meet modern aircraft design's strict power-to-weight requirements. Solutions based on emerging SiC and GaN technologies are the right tool for the job and well positioned to meet this challenge. 

 

AlGaN/GaN HEMT structure. Image used courtesy of STMicroelectronics

 

ST has a long history with SiC, introducing its first SiC diode in 2004, followed by the first SiC MOSFET in 2009. Along with a high energy band gap of three electronvolts (eV), silicon carbide is also much more thermally conductivity than silicon making it better suited for high-voltage (1200 V and higher) and power-dense applications. 

Gallium nitride on silicon (GaN/Si) is a more recent technology for ST and has a similar energy bandgap to SiC with even higher electron mobility. Lower gate charges and device capacitances allow for higher frequency operations that translate to more compact and lighter solutions, perfect for aviation applications. GaN has traditionally been limited to 650 V, but recent innovations across the industry are quickly pushing this boundary. 

In a GaN device, the AlGaN barrier between the Gate and GaN material allows for the formation of a 2D electron gas (2DEG) that supercharges the conduction channel for even more efficient operation.