Insights from Alexandros Mavronas, a System Application Engineer at Infineon Technologies.
The landscape of electrification is rapidly evolving, driven by the increasing demand for more compact, efficient, and sustainable power solutions. At the forefront of this transformation are Wideband Gap (WBG) technologies, namely Silicon Carbide (SiC) and Gallium Nitride (GaN). These advanced semiconductor materials are poised to redefine how we design and power everything from electric vehicles to industrial machinery. At the recent "Future of Electrification 2025" event, Alexandros Mavronas, a System Application Engineer at Infineon Technologies, explored how these innovative technologies are enabling the next generation of electrified systems.
The Power of Wideband Gap Technologies
At their core, wideband gap technologies derive their name from a fundamental property of semiconductor materials: the band gap energy. This energy gap represents the energy required to free electrons from their atomic bonds, allowing them to conduct electricity. SiC and GaN possess a band gap energy approximately three times higher than that of traditional silicon. This characteristic is directly correlated with their higher breakdown field, allowing for higher voltage operation and thinner active layers in devices.
Beyond their band gap, these materials also exhibit superior electron mobility, leading to higher switching frequencies and enhanced thermal conductivity, which improves heat dissipation. The combined effect of these properties means that WBG devices can achieve extended power density and significantly improved efficiency in designs.
Market Trends and Key Applications
While silicon remains the most widely used semiconductor technology, covering a vast range of applications from 25 volts up to 6.5 kilovolts, the market for wideband gap technologies is experiencing significant growth. SiC is enabling applications requiring slightly higher switching frequencies and high power, targeting voltages from 400 volts up to 3.3 kilovolts. GaN, though having a smaller current market size, shows an even higher expected growth rate due to its unique benefits, covering voltage classes from 40 volts up to 650 volts.
The adoption of WBG technologies is heavily dependent on the specific end application. For instance, silicon continues to be the preferred choice for cost-sensitive applications like power tools and certain railway applications due to its excellent cost-to-performance ratio. Silicon Carbide excels in high-power applications such as electric vehicle (EV) charging and energy storage systems, where its higher power density and efficiency play a crucial role. GaN, with its superior efficiency at higher switching frequencies, is increasingly found in automotive onboard chargers, consumer chargers, and server applications. This segmentation highlights that each technology will carve out its own key application areas in the future.
Driving Efficiency and Miniaturization Across Industries
Wideband gap technologies are not just theoretical improvements; they are actively enabling significant advancements in real-world applications.
Low Voltage Motor Drives: In applications like robotics, drones, and light electric vehicles (e-scooters, e-bikes), medium voltage GaN devices (e.g., 100V class) facilitate miniaturized designs capable of handling significant power, from a few hundred watts up to 20 kilowatts. GaN's unique properties, such as virtually no reverse recovery and lower gate charge, allow for lower switching losses and much higher switching frequencies. Moving a motor drive from 20 kHz to 100 kHz, for example, can reduce motor current ripple fivefold, make the motor run 13°C cooler, and boost overall system efficiency from 89% to 96%. Furthermore, GaN enables miniaturization by allowing the replacement of bulky electrolytic capacitors with smaller, high-performance ceramic capacitors.
Industrial and EV Battery Charging: In battery charging applications, WBG devices are crucial for achieving high efficiency. Topologies like the totem pole power factor correction (PFC) stage can achieve over 99% efficiency at 50% load, primarily because the fast-switching leg is enabled by SiC and GaN devices. In EV charging, whether AC wall boxes or high-power DC fast chargers, the efficiency gains are substantial. A 2% efficiency improvement in EV charging can lead to significant energy savings and CO2 reduction, or allow approximately 200,000 more cars to be charged for every 10 million on the road. The use of GaN bi-directional switches, for instance, can replace two silicon switches in PFC designs, further contributing to miniaturization and power density.
Automotive Applications (OBC, DCDC, Inverters): Modern electric cars demand high power density, efficiency, and bi-directionality for onboard chargers (OBCs), which can handle up to 22 kW and support vehicle-to-grid (V2G) or vehicle-to-vehicle (V2V) charging. GaN’s zero reverse recovery, low output capacitance, and excellent temperature dependency contribute to higher efficiency, lower EMI noise, and easier zero-voltage switching conditions in OBC and DCDC stages. For automotive inverters, critical for vehicle range, WBG technologies enable new multi-level topologies and significantly boost efficiency. For example, an 800V system utilizing a full Silicon Carbide solution can achieve about 6.5% more range compared to a standard silicon solution, while an advanced T-type inverter can push this to an impressive 11% more range. Marvonas mentioned that Infineon also innovates with "fusion modules" combining SiC MOSFETs and IGBTs to optimize performance across different load profiles in a single inverter.
Key Takeaways
- Unique Material Properties: Wideband gap semiconductors, particularly Silicon Carbide and Gallium Nitride, leverage superior material properties like higher breakdown voltage, faster switching speeds, and better thermal conductivity to create more efficient and compact power electronic designs.
- Application-Specific Advantages: Each WBG technology, along with conventional silicon, finds its "sweet spot" in different applications, allowing for optimized performance, cost, and power density across various sectors, from low-voltage motor drives to high-power EV charging.
- Significant Efficiency Gains: The adoption of WBG technologies leads to substantial improvements in system efficiency, translating directly into energy savings, reduced CO2 emissions, and extended range for electric vehicles.
- Miniaturization and Innovation: WBG devices enable higher power density and more compact designs, allowing for innovative power topologies that were previously unfeasible with silicon, driving forward the miniaturization of electrified systems.
- Addressed Challenges and Coexistence: While facing challenges related to manufacturing maturity, cost, and design complexity, ongoing efforts in standardization and reliability testing are paving the way for broader adoption. The future sees a complementary ecosystem where silicon, SiC, and GaN each play vital roles.
Challenges and Future Outlook
Despite their clear advantages, the widespread adoption of WBG devices faces certain challenges. The implementation of new, more complex topologies often requires sophisticated control algorithms, increasing software-related complexity. Furthermore, silicon technologies benefit from decades of manufacturing experience, utilizing larger 300mm wafers compared to the 6-inch or 8-inch wafers currently used for GaN and SiC, which impacts volume production and cost. While WBG manufacturing continues to improve, the initial cost can still be a barrier compared to established silicon solutions.
Regarding long-term reliability, industry standards like the JEDEC JC70 committee are specifically developed for WBG devices to establish quality checks and safeguard reliability by understanding their unique failure mechanisms.
Looking ahead, it's clear that wideband gap solutions will not completely replace silicon. Instead, all three technologies – silicon, SiC, and GaN – will coexist, each serving applications where their unique properties offer the best performance, cost, and efficiency trade-offs. Mavronas pointed out that Infineon continues to develop and enhance all three technologies, ensuring that the right solution is available for every application.
To learn more, watch the full session here: