GaN Valley and the International Semiconductor Executive Summits  join forces to advance GaN innovation and growth! ???? The partnership was made official last Friday, Sept 15th, during the I.S.E.S. Power EU summit in Italy.

With rapidly evolving GaN technology, and an expected $2.04B market by 2028, GaN is taking its place in the power semiconductor market. Recognizing the increasing importance of GaN technologies for the transition to a lower energy consuming society and sustainable future, GaN Valley and I.S.E.S. are joining forces to give their members the best possible opportunity for- and access to knowledge exchange, collaborations, education, research projects and events focused on GaN innovation and growth. 

The I.S.E.S. Power EU 2024 summit set for September 2024 in Italy, will welcome the GaN Valley as the exclusive co-host for the GaN focused day of the summit. Drawing from its knowledge, network and experience, the GaN Valley will be able to provide a premium contribution to an interesting and valuable day.

I.S.E.S. will be joining the GaN Valley flag event in the spring of 2024, where parties from along the European GaN supply chain will share their latest insights, research and innovations as well as work together on- or launch jointed projects. 

Members from both networks will benefit from the collaboration through gaining access, either free or at a discount, to the activities of the other party. This will be kicking off with I.S.E.S. members getting access to the member only (online) seminars of the GaN Valley. 

Besides this, the partners will join forces to share the latest insights on GaN developments and market reseach, as well as promote the GaN field and its innovations on an international and regional level, ensuring the accessibility of knowledge and expertise to those interested in, and ready for adopting new power solutions. 

Big thank you to Salah Nasri and Jubed Miah, we look forward to working closely with you! 

About The International Semiconductor Executive Summits (I.S.E.S.):
ISES is a leading global platform that brings together visionaries, thought leaders, and senior executives from the semiconductor industry. Our mission is to facilitate knowledge sharing, networking, and the exchange of ideas among key stakeholders in a trusted network, ensuring that innovation and progress continue to drive the industry forward.

About GaN Valley
GaN Valley is a leading technology hub specializing in Gallium Nitride (GaN), bringing together all parties along the supply chain to drive collaboration, education, research, development and innovation of GaN technologies and products, enabling market entry, adoption and growth.

BelGaN is building the foundation for the “GaN Valley^TM”, a growing and innovative ecosystem for GaN-based chips and power electronics with applications in Electrical Vehicle, Mobile, Industrial, Data Center and renewable energy markets in Europe and beyond. This is well aligned with the European ambition for greater chip autonomy (European Chips Act) and a carbon-neutral society (Green Deal).

Only a few months after its inception by BelGaN, the GaN Valley^TM ecosystem already counts over 40 member companies and institutions along the value chain of the GaN industry in Europe.

“Getting GaN into production is the first leap to realize our vision to build the GaN Valley^TM”, said Rob Willems, General Manager & VP Operations, BelGaN “While others took several years to bring GaN process and technology to manufacturing, we are able to do it in record one year leveraging more than 200 man-years of GaN technology development expertise with over 30 years of high-volume automotive production experiences”.

The BelGaN team and Fab started as MIETEC in 1983, it was acquired by Alcatel then AMIS, sold to onsemi in 2008, it started GaN development in 2009 and it has been building expertise in production of automotive semiconductors for more than 30 years. The site in Oudenaarde is currently transforming from a Silicon site to a GaN site. This will give an innovation-driven growth boost to the region and provide short- and long-term employment opportunities in Belgium with multiple career opportunities in R&D, operations, and various service departments. 

“These are exciting times for BelGaN and the GaN community” said Dr.Marnix Tack, CTO and VP Business Development, BelGaN “our Gen1 650V emode GaN technology is our entry platform in the market, targeting high energy-efficient soft switch applications, with a performance at par with industry leaders. It serves as the baseline for our Gen2 and Gen3 platforms that are currently under development for release later this year and early next year.”

BelGaN and GaN Valley^TM are driven by energy and climate mega-trends on increased electrification for higher sustainability and carbon neutrality (solar- and wind-energy, electric cars etc.), at affordable energy costs. E.g., according to industry experts, every GaN device shipped would save 4kg CO₂.

About BelGaN (www.belgan.com)：

BelGaN’s vision is to become a leading 6 inch and 8 inch GaN Foundry in Belgium, at the heart of Europe, developing GaN technologies and manufacturing GaN products. Going forward an extensive and rich roadmap of new GaN technologies including Gen2, Gen3, V-GaN，GaN-IC, will be developed and qualified for the high demands of the automotive market, amongst others.

About GaN Valley^TM（www.ganvalley.org)：

GaN Valley^TM targets a growing industry for electronic systems in which energy supply and usage of electrical energy will become increasingly more efficient (less energy waste), smaller, lighter, and lower cost compared to its Silicon counterpart. Since its launch in April, already over 40 companies and institutions in Europe joined and are supporting these initiatives.

Media Contact:

Marleen Polet

E: Marleen.Polet@belgan.com

Investor Contact:

Kapple Wang

E: Kapple.Wang@belgan.com

In the last couple of decades, the worldwide SiC and GaN scene has been characterised by development, growing industry acceptance.

In the last couple of decades, the worldwide SiC and GaN scene has been characterised by development, growing industry acceptance and the promise of billion-dollar revenues. The first commercial SiC device hit the scene in 2001 in the form of a Schottky diode from Germany’s Infineon. Rapid development has followed, and this industry sector is now poised to reach over $4 billion dollar market by 2026.

Meanwhile, GaN first wowed industry pundits in 2010 when US-based EPC delivered its super-fast switching transistors. Market adoption hasn’t yet matched that of SiC but come 2026, power GaN revenues could hit $1 billion.

The secret of future market success for each technology lies in electric and hybrid electric vehicles (EVs/HEVs). Indeed, for SiC, the EV/HEV market is truly the sweet-spot right now – at least 60% of the total market, which is in excess of $ 2.5B revenue, is expected to come from this sector.

Tesla kick-started the SiC power device market in 2017 when it became the first automaker to add SiC MOSFETs, sourced from STMicroelectronics, in an in-house main inverter design in its Model 3. Other automotive players have been quick to follow in EV giant’s footsteps, including Hyundai, BYD, Nio, General Motors and many others.

For example, China’s, Geely Automobile recently announced it is collaborating with ROHM, Japan on SiC-based traction inverters for its EVs, while NIO – China’s answer to Tesla – is to implement a SiC-based electric drive system in its vehicles. At the same time, OEM automaker and semiconductor manufacturer, BYD, has been developing SiC modules for its entire line of EVs.

Also, just last year, China-based electric bus manufacturer, Yutong, revealed it is to use SiC power modules manufactured by StarPower, China, in the power trains of its buses. These modules use SiC devices from Wolfspeed, US.

Over in Korea, Hyundai has turned to Infineon’s SiC-based power module for the 800 V battery platform of its electric vehicles while in Japan, Toyota is using SiC booster power modules from Denso in its Mirai fuel cell electric vehicles. And in the US, General Motors has just signed up Wolfspeed to supply SiC for its EV power electronics.

Europe tells a different story, where car manufacturers have been slower to embrace SiC, but change is afoot. In June this year, Renault and STMicroelectronics joined forces to develop SiC and GaN devices for EVs and HEVs, and more announcements are expected soon from Daimler, Audi and Volkswagen.

Importantly for the likes of Wolfspeed, Infineon, STMicroelectronics, ROHM and Onsemi, automotive OEMs also prefer to buy wafers and devices from multiple sources to ensure reliable supply. Factor in the vast sums of money that China, and increasingly other nations, are pouring into the SiC supply chain, and volume sales will only continue to rise.

And along the way, the thorny issue of cost is also being addressed. Without a doubt, at the component level, silicon IGBTs are vastly cheaper than the SiC equivalent, and are not going to disappear from power applications anytime soon. But Tier-1 manufacturers and OEMs have indicated that implementing high power density SiC into, say, an inverter design, cuts costs at a system level thanks to the space- and weight-savings that could stem from the need for fewer components.

But where does this leave GaN? This wide-bandgap semiconductor has yet to witness the success of SiC in the EV/HEV sector, but thanks to its high frequency operation and efficiencies, OEMs are either eyeing the technology with intense interest or have development programs underway.

Early days

GaN power devices can already be found in low volume, high end photovoltaic inverters and are being increasingly used in fast chargers for a range of mobile devices including smartphones. Indeed, Ireland’s Navitas, Power Integrations of the US, as well as Innoscience of China are all manufacturing GaN power ICs for the burgeoning fast charger market.

Given this activity, GaN power device revenues are estimated to reach around $100 million in 2021. But as GaN device suppliers look to enter other markets to raise volumes, this figure is expected to swell to that $1 billion by 2026. And the EV/HEV market is the first to watch.

It’s early days for GaN in electric vehicles. Many power GaN players have developed and auto-qualified 650 V GaN devices for onboard chargers and DC/DC conversion in EVs/HEVs, with myriad partnerships already formed with automotive businesses.

For example, Canada-based GaN Systems supplies its devices to US EV start-up, Canoo, for onboard chargers, and has also partnered with Canada-based EV motor drive supplier, FTEX, to integrate 650V GaN power devices into systems for e-scooters. At the same time, Transphorm, US, has teamed up with automotive supplier, Marelli, to provide devices for onboard charging and DC/DC conversion.

STMicroelectronics is expected to supply its yet-to-be auto-qualified devices to Renault for on EV applications, while EPC, now delivering automotive-qualified low voltage GaN, is working with French-based Brightloop to develop affordable power supply converters for off-high way and commercial vehicle. And last year, Texas Instruments also qualified its 650V GaN devices for automotive applications.

But as the onboard charger and DC/DC market segments gather momentum, the billion dollar question, quite literally, for GaN is will the technology make it to the main inverter of the EV/HEV powertrain, and reap spectacularly high volumes, and high revenues that SiC is beginning to see? Early industry developments indicate this is possible.

In February last year, Nexperia of The Netherlands hooked up with the UK consultants, Ricardo, to develop a GaN-based EV inverter design. The announcement was swiftly followed by VisIC Technologies of Israel partnering with German auto-supplier, ZF, to develop GaN semiconductors for 400 V driveline applications.

Then, in September this year, GaN Systems signed a $100 million deal with BMW to provide the capacity to manufacture GaN power devices for the German auto-maker’s electric vehicles, solid evidence that OEMs are serious about GaN. And in a truly significant step, Navitas is to become a publicly traded company with a market value of $1.04 billion, by combining with special-purpose acquisition company Live Oak Acquisition. The GaN power IC player recently announced it is to supply devices to Swiss-based Brusa HyPower for onboard chargers and DC/DC converters, and as a public company intends to put its weight behind product development for EVs/HEVs and other markets.

Beyond the deals, partnerships and mergers, early work on GaN modules also indicates that this compound semiconductor is following in the footsteps of SiC, with industry players gearing up for more widespread industry integration. For example, GaN Systems is offering a power evaluation module kit to design engineers while Transphorm has been working with Fujitsu General Electronics on a GaN module that targets industrial and automotive applications.

So, what next for both SiC and GaN? As manufacturers of power SiC devices ready for the multi-billion-dollar market that EVs/HEVs will bring, will GaN experience the same success story? Widespread OEM adoption of GaN in drivetrain inverters would radically impact market forecasts, but right now, we can only wait and see.

In its annual power semiconductor predictions, GaN Systems Inc of Ottawa, Ontario, Canada (a fabless developer of gallium nitride-based power switching semiconductors for power conversion and control applications) reckons that 2023 will be another landmark year for GaN — with the now widely adopted technology forecasted by Yole Intelligence’s ‘Power GaN 2022: Market and Technology Report 2022’ to reach $2bn by 2027, driven by rising adoption across consumer electronics, automotive, data centers, and sustainability initiatives.

The predictions explore the overarching systemic changes underway around the global semiconductor supply chain and sustainability initiatives specific to key power-reliant industries, i.e.

• Supply Chain – The initiation of historic multi-year programs to change where and how semiconductors are fabricated and packaged.
• Sustainability – Motivations for efficiency and conservation will concur with new political imperatives for energy independence. GaN isn’t just a good choice for high-frequency designs. It’s also good for the planet.
• Data Centers – GaN makes new inroads to become the solution of choice as data centers upgrade processors to optimize their ability to address profitability and sustainability goals.
• Electric Vehicles – GaN is integrated into designs for energy-efficient electric vehicles (EVs) and charging stations needed to meet the 2030 goals of auto manufacturers and global governments, businesses, and other organizations that influence the future of the automotive industry and road transport.
• Consumer Electronics – GaN is further entrenched in the mainstream with continuing innovations and new product releases in chargers, audio, appliances, and power tool designs.

“We are at the inflection point for power GaN technology,” believes GaN Systems. “Notwithstanding nearly three years of significant global economic and geopolitical headwinds, the GaN power semiconductor has established itself as a preferred product solution across multiple market segments, including data-center, electric vehicle, industrial, and consumer electronics industries. It has accomplished this by uniquely solving some of the most pressing and critical power systems challenges around energy efficiency and design in these industries,” adds the firm. “With the strong momentum of the electrification megatrend and an increasing number of products containing semiconductors, economic winners and losers will be determined mainly by those who can better manage their supply chains that not only enable the production of existing goods for businesses and consumers – yet stoke the fires of innovation for the near future.”

The predictions are specifically as follows:

PREDICTION 1
Supply Chain: Companies and Governments Embrace Multi-Billion-Dollar Long-Term Plans to Strengthen Global Semiconductor Fabrication and Packaging

• In the past, many companies focused on consolidating manufacturing activities in one or two countries. Looking ahead, the global semiconductor supply chain will work towards developing a substantial US presence in both engineering design and manufacturing. In the USA, this means embracing a national strategic semiconductor policy – rather than politically convenient.
• The CHIPS and Science Act of 2022 is expected to catalyze the geographic diversification of the semiconductor industry in the USA during the next four years. The substantial economic muscle in the form of $52.7bn in grants, loans and tax credits will drive investment in design, foundry and fabrication facilities. Large chip manufacturers will receive as much as $2.5-3bn for each new fabrication facility they build in the USA.
• To accelerate next-generation chip design and production, the broad investment program within the European Union (EU) Chips Act will focus on increasing production capacities and improving the ability to identify and respond to the semiconductor supply crises. Above all, the EU Chips Act aims to strengthen Europe’s research and technology leadership, which consists of the capabilities, capacities and controls necessary to act on long-term economic and societal objectives.
• Semiconductor packaging will be addressed in the shorter term, with factory additions in Vietnam and India. A large portion of semiconductor wafer fabrication will remain in Taiwan (68% of all semiconductors and 90% of advanced chips). This will continue to expose the semiconductor industry to regional ‘single source’ vulnerability as fabrication expansion in Europe, Canada and the USA builds out over several years.

PREDICTION 2
Sustainability: The Motivation for Energy Efficiency and Natural Resource Conservation Meets the Political Imperative of Energy Independence

• Sustainability and profitability will be dual drivers of business success. For example, using GaN semiconductors will concurrently increase revenue through greater data density in data centers and mitigate the environmental impact (e.g. meet aggressive ESG goals). Additionally, meeting sustainability metrics for products and operations will be as necessary as meeting performance and cost requirements.
• Pressures will increase for mass rollouts of technology for large-scale renewable energy collection, storage and use. More energy-efficient power inverters, DC-DC converters, and energy-dense storage will be needed in on-demand solar power systems. GaN technology will be at the center of this solution.
• In 2023 and beyond, there will be a natural acceleration of GaN demand to ensure a more sustainable future. The technology has been found to optimize power designs to decrease the carbon footprint of high-frequency devices and systems. GaN is uniquely positioned to enable a greener, more carbon-neutral future for the electronics industry. GaN power semiconductors aim to conserve energy and miniaturize devices by capitalizing on high switching speeds and low ON resistance.

PREDICTION 3
Data Centers – Profitability Meet Sustainability Initiatives in the Move to Greater GaN Technology Adoption

• As data centers refresh hardware every three to five years, compounded with the EU Eco-design Lot 9 efficiency regulatory requirements in effect, there will be a significant opportunity for GaN to replace silicon in both rackmount power supplies and the individual redundant power supplies in servers. This upgrade of servers and build-out of server racks using GaN power supplies will be led by the innovative work from OEMs such as Intel and HP. More server and rack power supply companies will follow, adopting GaN and making GaN ‘the standard’ for the industry.
• New standards from tech giants will accelerate change to higher efficiency and smaller form factors for power supplies. The Open Computer Project (OCP) defines a new standard form factor, M-CRPS, for a server’s power supply that decreases the size by 30%. Legacy transistor technology, namely silicon MOSFETs, will struggle to deliver on this standard while GaN excels here. Additionally, OCP designs, many targeted for hyperscale computing, have increasing demands for very high energy efficiency, a characteristic best delivered by GaN.
• The demands on power supplies will increase the use of GaN: (1) to increase efficiency via its properties of lower switching and conduction losses, (2) to increase power density via operating at higher frequencies than the ability of alternative technologies, and (3) smaller and more highly efficient GaN-based power supplies directly lower a data center’s power bills and indirectly reduce cooling system costs.

PREDICTION 4
Electric Vehicles: Pressures Intensify to Accelerate the Move to EVs from Both the Moral Motivations of Climate Change and the realities of Energy Economics

• Automotive OEMs and their tier 1 suppliers will continue to make decisions about their power transistor choices through the four lenses of performance, reliability, cost and capacity. High-performance GaN solutions in the design stage in 2022-2023 will be mainstream in 2025-2026, delivering lower cost and more energy-efficient power solutions.
• OEMs are increasingly moving into production with GaN, which will accelerate in 2023. GaN semiconductor companies will begin to see their share of EV designs increase as more 400V system designs rise in importance, multi-level GaN solutions for 800V systems are validated, and silicon carbide (SiC) experiences continued material shortages, yield challenges and cost concerns.

PREDICTION 5
Consumer Electronics: GaN Becomes Mainstream in Multiple Consumer Markets

• GaN will increase its share in chargers from the popular 45W and 65W chargers to the growing market for higher-power 100-180W chargers with both single and multiple port variations, delivering ultrafast and multi-device charging experiences to consumers.
• For audio, GaN will enable mainstream brands to fulfill consumers’ mobile and voice-activated lifestyle demands with more compact form factors that deliver the same volume and audio quality of much larger devices.
• New Class D audio systems design will accelerate with the adoption of ‘building blocks’ for GaN products that enable audio systems designers across markets to mix and match designs and maximize performance for their specific applications.
• Growth in new application areas, such as home appliances, large-screen TVs, E-bikes and power tools, will result from companies’ acknowledgment of GaN’s mainstream position and value in consumer electronics and their validation of GaN-based system designs. Innovative GaN-powered products in these markets will hit the consumer market in 2023-2024.

“As global companies continue to face pressure to drive both profitability and sustainability, GaN technology takes on an even higher level of importance,” says GaN Systems’ CEO Jim Witham. “Despite significant global economic and geopolitical headwinds of the last three years, GaN is now recognized as a widely adopted technology estimated to reach $2bn by 2027, driven by rising use in consumer electronics, automotive applications, data centers, and industrial and electric vehicles. As such, companies will continue to accelerate their commitment to greater energy efficiency, and we’ll see profitability and sustainability drive $6bn GaN growth.”

Starting around 2001, the compound semiconductor gallium nitride fomented a revolution in lighting that has been, by some measures, the fastest technology shift in human history. In just two decades, the share of the global lighting market held by gallium-nitride-based light-emitting diodes has gone from zero to more than 50 percent, according to a study by the International Energy Agency. The research firm Mordor Intelligence recently predicted that, worldwide, LED lighting will be responsible for cutting the electricity used for lighting by 30 to 40 percent over the next seven years. Globally, lighting accounts for about 20 percent of electricity use and 6 percent of carbon dioxide emissions, according to the United Nations Environment Program.

Each wafer contains hundreds of state-of-the-art power transistorsPETER ADAMS
This revolution is nowhere near done. Indeed, it is about to jump to a higher level. The very semiconductor technology that has transformed the lighting industry, gallium nitride (GaN), is also part of a revolution in power electronics that is now gathering steam. It is one of two semiconductors—the other being silicon carbide (SiC)—that have begun displacing silicon-based electronics in enormous and vital categories of power electronics.

GaN and SiC devices perform better and are more efficient than the silicon components they are replacing. There are countless billions of these devices all over the world, and many of them operate for hours every day, so the energy savings are going to be substantial. The rise of GaN and SiC power electronics will ultimately have a greater positive impact on the planet’s climate than will the replacement of incandescent and other legacy lighting by GaN LEDs.

Virtually everywhere that alternating current must be transformed to direct current or vice versa, there will be fewer wasted watts. This conversion happens in your phone’s or laptop’s wall charger, in the much larger chargers and inverters that power electric vehicles, and elsewhere. And there will be similar savings as other silicon strongholds fall to the new semiconductors, too. Wireless base-station amplifiers are among the growing applications for which these emerging semiconductors are clearly superior. In the effort to mitigate climate change, eliminating waste in power consumption is the low-hanging fruit, and these semiconductors are the way we’ll harvest it.

This is a new instance of a familiar pattern in technology history: two competing innovations coming to fruition at the same time. How will it all shake out? In which applications will SiC dominate, and in which will GaN prevail? A hard look at the relative strengths of these two semiconductors gives us some solid clues.

Why Power Conversion Matters in Climate Calculations

Before we get to the semiconductors themselves, let’s first consider why we need them. To begin with: Power conversion is everywhere. And it goes far beyond the little wall chargers that sustain our smartphones, tablets, laptops, and countless other gadgets.

Power conversion is the process that changes electricity from the form that’s available to the form required for a product to perform its function. Some energy is always lost in that conversion, and because some of these products run continuously, the energy savings can be enormous. Consider: Electricity consumption in the state of California remained essentially flat from 1980 even as the economic output of the state skyrocketed. One of the most important reasons why the demand remained flat is that the efficiency of refrigerators and air conditioners increased enormously over that period. The single-greatest factor in this improvement has been the use of variable-speed drives based on the insulated gate bipolar transistor (IGBT) and other power electronics, which greatly increased efficiency.

Gallium Nitride and Silicon Carbide: Where They Compete

In the markets for high-voltage power transistors, gallium nitride devices dominate in applications below around 400 volts, while silicon carbide has the edge now for 800 V and above (the markets are relatively small above around 2,000 V). The landscape of the important battleground between 400 and 1,000 V will change as GaN devices improve. For example, with the introduction of 1,200-V GaN transistors—expected in 2025—the battle will be joined in the all-important market for electric-vehicle inverters.CHRIS PHILPOT

SiC and GaN are going to enable far greater reductions in emissions. GaN-based technologies alone could lead to a savings of over 1 billion tonnes of greenhouse gases in 2041 in just the United States and India, according to an analysis of publicly available data by Transphorm, a GaN-device company I cofounded in 2007. The data came from the International Energy Agency, Statista, and other sources. The same analysis indicates a 1,400-terawatt-hour energy savings—or 10 to 15 percent of the projected energy consumption by the two countries that year.

Wide-Bandgap’s Advantages

Like an ordinary transistor, a power transistor can act as an amplifying device or as a switch. An important example of the amplifying role is in wireless base stations, which amplify signals for transmission to smartphones. All over the world, the semiconductor used to fabricate the transistors in these amplifiers is shifting from a silicon technology called laterally diffused metal-oxide semiconductor (LDMOS) to GaN. The newer technology has many advantages, including a power-efficiency improvement of 10 percent or more depending on frequencies. In power-conversion applications, on the other hand, the transistor acts as a switch rather than as an amplifier. The standard technique is called pulse-width modulation. In a common type of motor controller, for example, pulses of direct-current electricity are fed to coils mounted on the motor’s rotor. These pulses set up a magnetic field that interacts with that of the motor’s stator, which makes the rotor spin. The speed of this rotation is controlled by altering the length of the pulses: A graph of these pulses is a square wave, and the longer the pulses are “on” rather than “off,” the more rotational speed and torque the motor provides. Power transistors accomplish the on-and-off switching.

This article was jointly produced by IEEE Spectrum and Proceedings of the IEEE with similar versions published in both publications.

Pulse-width modulation is also used in switching power supplies, one of the most common examples of power conversion. Switching power supplies are the type used to power virtually all personal computers, mobile devices, and appliances that run on DC. Basically, the input AC voltage is converted to DC, and then that DC is “chopped” into a high-frequency alternating-current square wave. This chopping is done by power transistors, which create the square wave by switching the DC on and off. The square wave is applied to a transformer that changes the amplitude of the wave to produce the desired output voltage. To get a steady DC output, the voltage from the transformer is rectified and filtered.

The important point here is that the characteristics of the power transistors determine, almost entirely, how well the circuits can perform pulse-width modulation—and therefore, how efficiently the controller regulates the voltage. An ideal power transistor would, when in the off state, completely block current flow even when the applied voltage is high. This characteristic is called high electric breakdown field strength, and it indicates how much voltage the semiconductor is able to withstand. On the other hand, when it is in the on state, this ideal transistor would have very low resistance to the flow of current. This feature results from very high mobility of the charges—electrons and holes—within the semiconductor’s crystalline lattice. Think of breakdown field strength and charge mobility as the yin and yang of a power semiconductor.

GaN transistors are very unusual because most of the current flowing through them is due to electron velocity rather than electron charge.

GaN and SiC come much closer to this ideal than the silicon semiconductors they are replacing. First, consider breakdown field strength. Both GaN and SiC belong to a class called wide-bandgap semiconductors. The bandgap of a semiconductor is defined as the energy, in electron volts, needed for an electron in the semiconductor lattice to jump from the valence band to the conduction band. An electron in the valence band participates in the bonding of atoms within the crystal lattice, whereas in the conduction band electrons are free to move around in the lattice and conduct electricity.

In a semiconductor with a wide bandgap, the bonds between atoms are strong and so the material is usually able to withstand relatively high voltages before the bonds break and the transistor is said to break down. The bandgap of silicon is 1.12 electron volts, as compared with 3.40 eV for GaN. For the most common type of SiC, the band gap is 3.26 eV. [See table below, “The Wide-Bandgap Menagerie”]

The Wide-Bandgap Menagerie

Speed of operation and the ability to block high voltage are two of the most important characteristics of a power transistor. These two qualities are in turn determined by key physical parameters of the semiconductor materials used to fabricate the transistor. Speed is determined by the mobility and velocity of charges in the semiconductor, while voltage blocking is established by the material’s bandgap and electric breakdown field. Source: The Application of Third Generation Semiconductor in Power Industry, Yuqian Zhang, E3S Web of Conferences, Volume 198, 2020

Now let’s look at mobility, which is given in units of centimeters squared per volt second (cm ²/V·s). The product of mobility and electric field yields the velocity of the electron, and the higher the velocity the higher the current carried for a given amount of moving charge. For silicon this figure is 1,450; for SiC it is around 950; and for GaN, about 2,000. GaN’s unusually high value is the reason why it can be used not only in power-conversion applications but also in microwave amplifiers. GaN transistors can amplify signals with frequencies as high as 100 gigahertz—far above the 3 to 4 GHz generally regarded as the maximum for silicon LDMOS. For reference, 5G’s millimeter-wave frequencies top out at 52.6 GHz. This highest 5G band is not yet widely used, however, frequencies up to 75 GHz are being deployed in dish-to-dish communications, and researchers are now working with frequencies as high as 140 GHz for in-room communications. The appetite for bandwidth is insatiable.

These performance figures are important, but they’re not the only criteria by which GaN and SiC should be compared for any particular application. Other critical factors include ease of use and cost, for both the devices and the systems into which they are integrated. Taken together, these factors explain where and why each of these semiconductors has begun displacing silicon—and how their future competition may shake out.

SiC Leads GaN in Power Conversion Today…

The first commercially viable SiC transistor that was superior to silicon was introduced by Cree (now Wolfspeed) in 2011. It could block 1,200 volts and had a respectably low resistance of 80 milliohms when conducting current. Today there are three different kinds of SiC transistors on the market. There’s a trench MOSFET (metal-oxide semiconductor field-effect transistor) from Rohm; DMOSs (double-diffused MOSs) from Infineon Technologies, ON Semiconductor Corp., STMicroelectronics, Wolfspeed, and others; and a vertical-junction field-effect transistor from Qorvo.

One of the big advantages of SiC MOSFETs is their similarity to traditional silicon ones—even the packaging is identical. A SiC MOSFET operates in essentially the same way as an ordinary silicon MOSFET. There’s a source, a gate, and a drain. When the device is on, electrons flow from a heavily doped n-type source across a lightly doped bulk region before being “drained” through a conductive substrate. This similarity means that there’s little learning curve for engineers making the switch to SiC.

Compared to GaN, SiC has other advantages. SiC MOSFETs are inherently “fail-open” devices, meaning that if the control circuit fails for any reason the transistor stops conducting current. This is an important feature, because this characteristic largely eliminates the possibility that a failure could lead to a short circuit and a fire or explosion. (The price paid for this feature, however, is a lower electron mobility, which increases resistance when the device is on.)

…But GaN Is Gaining

GaN brings its own unique advantages. The semiconductor first established itself commercially in 2000 in the markets for light-emitting diodes and semiconductor lasers. It was the first semiconductor capable of reliably emitting bright green, blue, purple, and ultraviolet light. But long before this commercial breakthrough in optoelectronics, I and other researchers had already demonstrated the promise of GaN for high-power electronics. GaN LEDs caught on quickly because they filled a void for efficient lighting. But GaN for electronics had to prove itself superior to existing technologies: in particular, silicon CoolMOS transistors from Infineon for power electronics, and silicon-LDMOS and gallium-arsenide transistors for radio-frequency electronics.

GaN’s main advantage is its extremely high electron mobility. Electric current, the flow of charge, equals the concentration of the charges multiplied by their velocity. So you can get high current because of high concentration or high velocity or some combination of the two. The GaN transistor is unusual because most of the current flowing through the device is due to electron velocity rather than charge concentration. What this means in practice is that, in comparison with Si or SiC, less charge has to flow into the device to switch it on or off. That, in turn, reduces the energy needed for each switching cycle and contributes to high efficiency.

Enhancement-Mode GaN Transistor

One of the two major types of gallium nitride transistor is called an enhancement-mode device. It uses a gate-control circuit operating at around 6 volts to control the main switching circuit, which can block 600 V or more when the control circuit is off. When the device is on (when 6 V are applied to the gate), electrons flow from the drain to the source in a flat region called a two-dimensional electron gas. In this region the electrons are extremely mobile—a factor that helps enable very high switching speeds—and confined beneath a barrier of aluminum gallium nitride. When the device is off, the region below the gate is depleted of electrons, breaking the circuit under the gate and stopping current flow.CHRIS PHILPOT

Meanwhile, GaN’s high electron mobility allows switching speeds on the order of 50 volts per nanosecond. That characteristic means power converters based on GaN transistors operate efficiently at frequencies in the multiple hundreds of kilohertz, as opposed to about 100 kilohertz for silicon or SiC.

Taken together, the high efficiency and high frequency enables the power converter based on GaN devices to be quite small and lightweight: High efficiency means smaller heat sinks, and operation at high frequencies means that the inductors and capacitors can be very small, too.

One disadvantage of GaN semiconductors is that they do not yet have a reliable insulator technology. This complicates the design of devices that are fail-safe—in other words, that fail open if the control circuit fails.

There are two options to achieve this normally off characteristic. One is to equip the transistor with a type of gate that removes the charge in the channel when there’s no voltage applied to the gate and that conducts current only on application of a positive voltage to that gate. These are called enhancement-mode devices. They are offered by EPC, GaN Systems, Infineon,Innoscience, and Navitas, for example. [See illustration, “Enhancement-ModeGaNTransistor”]

The other option is called the cascode solution. It uses a separate, low-loss silicon field-effect transistor to provide the fail-safe feature for the GaN transistor. This cascode solution is used by Power Integrations, Texas Instruments, and Transphorm. [See illustration, “Cascoded Depletion-Mode GaN Transistor”]

Cascoded Depletion-Mode GaN Transistor

For safety, when a power transistor’s control circuit fails, it must fail into the open state, with no current flow. This is a challenge for gallium nitride devices because they lack a gate-insulator material that is reliable both in the high-voltage blocking state and in the current-carrying on state. One solution, called cascoded depletion-mode, uses a low-voltage signal on a silicon field-effect transistor (FET) to control the much larger voltage on a gallium nitride high electron mobility transistor [above right]. If the control circuit fails, the voltage on the gate of the FET drops to zero and it stops conducting current [above left]. With the FET no longer conducting current, the gallium nitride transistor also stops conducting, because there is no longer a closed circuit between the drain and the source of the combined device. CHRIS PHILPOT

No comparison of semiconductors is complete without a consideration of costs. A rough rule of thumb is—smaller die size means lower cost. Die size is the physical area of the integrated circuit containing the devices.

SiC devices now generally have smaller dies than GaN ones. However, SiC’s substrate and fabrication costs are higher than those for GaN and, in general, the final device costs for applications at 5 kilowatts and higher are not much different today. Future trends, though, are likely to favor GaN. I base this belief on the relative simplicity of GaN devices, which will mean production costs low enough to overcome the larger die size.

That said, for GaN to be viable for many high-power applications that also demand high voltages, it must have a cost-effective, high-performance device rated for 1,200 V. After all, there are already SiC transistors available at that voltage. Currently, the closest commercially available GaN transistors are rated for 900 V, produced by Transphorm, which I cofounded with Primit Parikh. Lately, we have also demonstrated 1,200-V devices, fabricated on sapphire substrates, that have both electrical and thermal performance on a par with SiC devices.

Projections from the research firm Omdia for 1,200-V SiC MOSFETs indicate a price of 16 cents per ampere in 2025. In my estimation, because of the lower cost of GaN substrates, the price of first-generation 1,200-V GaN transistors in 2025 will be less than that of their SiC counterparts. Of course, that’s just my opinion; we’ll all know for sure how this will shake out in a couple of years.

GaN vs. SiC: Handicapping the Contests

With these relative advantages and disadvantages in mind, let’s consider individual applications, one by one, and shed some light on how things might develop.

• Electric vehicle inverters and converters: Tesla’s adoption of SiC in 2017 for the onboard, or traction, inverters for its Model 3 was an early and major win for the semiconductor. In an EV, the traction inverter converts the DC from the batteries to AC for the motor. The inverter also controls the speed of the motor by varying the frequency of the alternating current. Today, Mercedes-Benz and Lucid Motors are also using SiC in their inverters and other EV makers are planning to use SiC in upcoming models, according to news reports. The SiC devices are being supplied by Infineon, OnSemi, Rohm, Wolfspeed, and others. EV traction inverters typically range from about 35 kW to 100 kW for a small EV to about 400 kW for a large vehicle.

However, it’s too soon to call this contest for SiC. As I noted, to make inroads in this market, GaN suppliers will have to offer a 1,200-V device. EV electrical systems now typically operate at just 400 volts, but the Porsche Taycan has an 800-V system, as do EVs from Audi, Hyundai, and Kia. Other automakers are expected to follow their lead in coming years. (The Lucid Air has a 900-V system.) I expect to see the first commercial 1,200-V GaN transistors in 2025. These devices will be used not only in vehicles but also in high-speed public EV chargers.

The higher switching speeds possible with GaN will be a powerful advantage in EV inverters, because these switches employ what are called hard-switched techniques. Here, the way to enhance performance is to switch very fast from on to off to minimize the time when the device is both holding high voltage and passing high current.

Besides an inverter, an EV also typically has an onboard charger, which enables the vehicle to be charged from wall (mains) current by converting AC to DC. Here, again, GaN is very attractive, for the same reasons that make it a good choice for inverters.

• Electric-grid applications: Very-high-voltage power conversion for devices rated at 3 kV and higher will remain the domain of SiC for at least the next decade. These applications include systems to help stabilize the grid, convert AC to DC and back again at transmission-level voltages, and other uses.

• Phone, tablet, and laptop chargers: Starting in 2019, GaN-based wall chargers became available commercially from companies such as GaN Systems, Innoscience, Navitas, Power Integrations, and Transphorm. The high switching speeds of GaN coupled with its generally lower costs have made it the incumbent in lower-power markets (25 to 500 W), where these factors, along with small size and a robust supply chain, are paramount. These early GaN power converters had switching frequencies as high as 300 kHz and efficiencies above 92 percent. They set records for power density, with figures as high as 30 W per cubic inch (1.83 W/cm³)—roughly double the density of the silicon-based chargers they are replacing.

An automated system of probes applies a high voltage to stress test power transistors on a wafer. The automated system, at Transphorm, tests each one of some 500 die in minutes. PETER ADAMS

• Solar-power microinverters: Solar-power generation has taken off in recent years, in both grid-scale and distributed (household) applications. For every installation, an inverter is needed to convert the DC from the solar panels to AC to power a home or release the electricity to the grid. Today, grid-scale photovoltaic inverters are the domain of silicon IGBTs and SiC MOSFETs. But GaN will begin making inroads in the distributed solar market, particularly.

Traditionally, in these distributed installations, there was a single inverter box for all of the solar panels. But increasingly installers are favoring systems in which there is a separate microinverter for each panel, and the AC is combined before powering the house or feeding the grid. Such a setup means the system can monitor the operation of each panel in order to optimize the performance of the whole array.

Microinverter or traditional inverter systems are critical to the modern data center. Coupled with batteries they create an uninterruptible power supply to prevent outages. Also, all data centers use power-factor correction circuits, which adjust the power supply’s alternating-current waveforms to improve efficiency and remove characteristics that could damage equipment. And for these, GaN provides a low-loss and economical solution that is slowly displacing silicon.

• 5G and 6G base stations: GaN’s superior speed and high power density will enable it to win and ultimately dominate applications in the microwave regimes, notably 5G and 6G wireless, and commercial and military radar. The main competition here are arrays of silicon LDMOS devices, which are cheaper but have lower performance. Indeed, GaN has no real competitor at frequencies of 4 GHz and above.

For 5G and 6G wireless, the critical parameter is bandwidth, because it determines how much information the hardware can transmit efficiently. Next-generation 5G systems will have nearly 1 GHz of bandwidth, enabling blazingly fast video and other applications.

Microwave-communication systems that use silicon-on-insulator technologies provide a 5G+ solution using high-frequency silicon devices where each device’s low output power is overcome with large arrays of them. GaN and silicon will coexist for a while in this space. The winner in a specific application will be determined by a trade-off among system architecture, cost, and performance.

• Radar: The U.S. military is deploying many ground-based radar systems based on GaN electronics. These include the Ground/Air Task Oriented Radar and the Active Electronically Scanned Array Radar built by Northrup-Grumman for the U.S. Marine Corps. Raytheon’s SPY6 radar was delivered to the U.S. Navy and tested for the first time at sea in December 2022. The system greatly extends the range and sensitivity of shipborne radar.

The Wide-Bandgap Battle Is Just Beginning

Today, SiC dominates in EV inverters, and generally wherever voltage-blocking capability and power handling are paramount and where the frequency is low. GaN is the preferred technology where high-frequency performance matters, such as in base stations for 5G and 6G, and for radar and high-frequency power-conversion applications such as wall-plug adapters, microinverters, and power supplies.

But the tug-of-war between GaN and SiC is just beginning. Regardless of how the competition plays out, application by application and market by market, we can say for sure that the Earth’s environment will be a winner. Countless billions of tonnes of greenhouse gases will be avoided in coming years as this new cycle of technological replacement and rejuvenation wends its way inexorably forward.