The Influence of GaN on Power Electronics Design

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— Part of an ongoing EE Times series: Diversity & Belonging in EE.  Previous parts can be found here.

Since the development of wide-bandgap (WBG) materials like silicon carbide (SiC) and gallium nitride (GaN), power electronics technologies have experienced a significant revolution. In fact, these materials possess properties that make them especially well-suited for applications that run at high switching frequencies and voltages, providing more efficiency and thermal control than even the most sophisticated silicon-based power devices.

There’s a large chance of achieving net-zero goals if next-generation semiconductor GaN is used in power-conversion devices rather than traditional silicon chips. Due to increasing social pressure and more stringent rules requiring lower CO2 emissions, industries ranging from automotive to telecom are being driven to invest in more efficient power conversion and electrification.

Energy usage for human activity is growing. In 2019, the globe used 23,000 TWh of energy and added 36.7 gigatons of CO2 to the atmosphere as a result, according to estimates. Only by making investments in cleaner energy generation and conversion will it be possible to achieve the target of net-zero CO2 emissions by 2050.

This entails increasing productivity in the crucial fields of electric mobility, the production of renewable energy and data-intensive computer applications like cloud computing and 5G. In order to achieve climate change targets, energy production must be more efficient. The semiconductor industry has made over $10 billion in WBG technology as part of this initiative.

GaN is thought to be the most promising and cutting-edge power technology. In terms of switching speed, thermal conductivity and reduced drain-to-source resistance, GaN-based power devices have surpassed conventional silicon devices. For power conversion and management, GaN technologies are becoming more and more common in a variety of applications, including high-power motor drives, quick-charging adapters, telecom, high-performance computing and space applications.

In an interview with EE Times, VisIC Technologies CEO and co-founder Tamara Baksht and Cambridge GaN Devices (CGD) CEO Giorgia Longobardi shared their insights about GaN technology.

CGD, a spin-out of Cambridge University, is a fabless semiconductor company that designs, develops and commercializes energy-efficient GaN-based power devices to make greener electronics possible. VisIC Technologies was founded in 2010 to mainstream D3GaN technology; the development team optimized a dependable, high-voltage, high-current (650 V, 200 A) transistor design based on fundamental research.

Here’s what Baksht and Longobardi had to say.

What inspired you to focus on GaN technology and its potential in the power electronics industry?

Tamara Baksht: We depend on electric energy more and more with each coming year. Just imagine 24 hours without electricity. The governmental regulations to use electrical energy instead of mechanical energy and to be net-zero by 2050 are making this dependence on electrical energy even more substantial. GaN devices can efficiently handle orders of magnitude more power at the same frequency, or orders of magnitude higher frequency at the same power compared with silicon semiconductors, and are significantly more accessible from a manufacturing and supply chain point of view than SiC. Therefore, reliable and high-performing GaN power switches will have an enormous impact on the industry and people’s life quality: A few percent improvements in efficiency in power supplies will bring terawatts of saved energy. Or tens of miles of additional driving distance for electric cars with the same battery. Or smaller and lighter industrial motors for construction or industrial robots. Or all of this together. Plus, they are making power-hungry AI chips easier and more sustainable.

Giorgia Longobardi: I came to the U.K. for an Erasmus program for my master’s thesis. Not much work had been done on GaN as a material for high-efficiency power devices, and I like a challenge—I like to shape the unknown and have a wider impact. So I picked GaN.

How do you envision GaN technology shaping the future of power electronics and its impact on various industries?

Cambridge GaN Devices’ Giorgia Longobardi.Cambridge GaN Devices’ Giorgia Longobardi.
Cambridge GaN Devices’ Giorgia Longobardi

Longobardi: We are only at the beginning of understanding what GaN can do. Initially, there was a reluctance to adopt new technology, so it was slow to take off, but now, it’s booming. The interesting thing about GaN is that it isn’t only a high-efficiency technology, with performance close to the ideal switch; it’s also a lateral technology. This means that circuit elements can be integrated monolithically, leading to miniaturization and the adoption of other approaches concerning device protection, ease of use and reliability. So there’s a world of innovation that lateral GaN enables, which means that it will—and is being used in—industrial markets, data centers, solar installations and other technologies that will help detach the home from the grid. The idea is that a solar panel on a house will be used to charge the car, and then the car provides electricity for the house. So GaN can play a huge role, both in solar and automotive.

How does your company differentiate itself in the GaN technology market, and what’s your vision for its growth and success?

Baksht: VisIC Technologies is entirely focused on the inverter propulsion market for electric vehicles, as we think this is where GaN today can bring the highest value, enabling more affordable cars with longer driving mileage. This is a huge, fast-growing market, and we have a rare opportunity to save the world, do a profitable business and make our customers and the customers of our customers happy.

Longobardi: People like new technologies, but they don’t like change. So our idea is to give them something—GaN—that has all the advantages of efficiency, high frequency and high power density but which “looks” like silicon. Our secret is that you can use any silicon gate driver with our GaN, so the technology is easy to use. We have also created a very smart solution by integrating monolithically not only the driver interface but also protection circuitry, ensuring a very robust and reliable solution. It’s a simple concept but complex to achieve.

Our vision is to take this technology and use it to open up markets like industrial and automotive so that CGD is one of the first players shaping these exciting opportunities with high-efficiency GaN. We are growing rapidly, opening up offices worldwide to support our customers so that they can deploy energy-efficient, sustainable solutions.

What is the biggest challenge you have faced in your career, and how did you overcome it?

VisIC Technologies’ Tamara Baksht.VisIC Technologies’ Tamara Baksht.
VisIC Technologies’ Tamara Baksht

Baksht: I came to Israel at 28 years old with my husband and a 4-year–old daughter, with an M.Sc. degree in solid-state physics but without any knowledge of the Hebrew language and with no savings. I started working as a table helper (just below the waiter in the hierarchy) in a neighboring resort village in parallel to learning the entry-level Hebrew language.

The main challenge was to be promoted (I aimed for room service manager) and to have time to study the language during the shifts. Without the language, getting along in a foreign culture was challenging, but I knew it would help me accomplish all I wanted.

I decided to take responsibility, get things done, complete all my tasks, help my managers and keep my head above water constantly. It was the autumn of 1999, and the number of tourists in the resort village at Galilee Lake had been enormous. In three months, I had been promoted, and by the end of our living there, in another three months, I got an offer to be in the permanent position of hospitality service manager. They were stunned when I explained that my specialty was in physics and I was moving to start my Ph.D. in Tel Aviv.

After this challenge, all other multiple challenges I met were comparatively easier to tackle.

Longobardi: There are many challenges. Some are associated with being a startup, but innovation often comes from startups. However, I invest a lot of time introducing the company, because we haven’t been around for very long. Sometimes people are surprised to hear that we have 50 people and eight products in mass production with a very secure supply chain. It’s about removing that barrier-to-entry perception that a startup can grow fast and be successful.

Also, because we come from academia, we have to prove ourselves as businesspeople, too, and there’s a lot to learn. I would also say that, as a woman coming from academia, I am very different from the majority of other business leaders. But we embrace that diversity because it enables CGD to be innovative in the way we do business, as well as through our technology.

I am a fighter, and I have the drive to make a change. The more I can empower younger women to realize that GaN is a cool field where they can succeed, the easier it’s going to be for others. So we encourage diversity and a different way of thinking, which is a power that many people underestimate.

What role does GaN technology play in achieving sustainability and reducing energy consumption in various industries?

Baksht: GaN power technology is an enabler for a sustainable world in both aspects of usage and manufacturing. As a usage, higher efficiency of GaN power switches will save a humongous amount of energy: Raising efficiency from 95% to 98% reduces power losses by 60%. With losses in conversion worldwide of hundreds of terawatts, even a 10% to 20% savings means no need for new-generation power plants, saving resources and achieving better sustainability. Regarding manufacturing, GaN is about 10× more sustainable than SiC.

Longobardi: GaN can have a huge impact in reducing energy waste and achieving sustainability, which is one reason why it’s important for our messages to reach a wider political and consumer audience, even though we know it’s the engineering community that will design GaN devices into products. It’s predicted that there will be 240 million EVs on the road by 2030 and that the yearly electricity demand for data centers will be 800 TWh. This is why CGD wants to address these fields in particular, as we can make the most difference.

Can you share any insights or advice for aspiring entrepreneurs or professionals interested in the field of GaN technology and its applications?

Baksht: GaN looks similar to traditional silicon or SiC power devices, but its physics, failure mechanisms and consequent design radically differ. When you start to play with GaN, be sure you have GaN HEMT–trained specialists on your team.

Longobardi: First, be aware of just how much GaN can enable in terms of reducing CO2 emissions and increasing sustainability. It’s a truly beneficial technology, and therefore, being involved with GaN is an occupation that’s very worthwhile indeed. Second, take it one step at a time—because there’s a lot of hard work involved. Believe in yourself and surround yourself with people who can provide good advice and insights. The other vital element is to have passion and be aware of your strengths. Don’t do it unless you believe in it. But if you do believe, you can succeed with your unique vision and make a game-changing contribution.