The man behind the IGBT: An interview with Prof. Jayant Baliga (BT/EE/1969)


Prof. Jayant Baliga is an internationally recognized expert on power semiconductor devices. He is a Member of the National Academy of Engineering, a Fellow of the IEEE, and Distinguished University Professor at NCSU. Prof. Baliga has 18 books and well over 500 scientific articles to his credit and holds 120 U.S. patents. He is most well known for having invented, developed and commercialized the Insulated Gate Bipolar Transistor (IGBT) at GE.

For his work, Prof. Baliga has received numerous top honours and awards, including notably the Global Energy Prize, the National Medal of Technology and Innovation, and was named “One of the 8 Heroes of the Semiconductor Revolution” by Scientific American, to name just a few. In 2000, IIT Madras honoured him with the Distinguished Alumnus Award.

IIT Madras had the honour of receiving Prof. Baliga as the Chief Guest presiding over the 53rd Convocation Ceremony of the institute this year. The day before the Convocation, Prof. Baliga gave a talk titled “The IGBT Miracle: From Conception to Global Impact”. The talk was well attended by students, professors, alumni and dignitaries. Describing the origins of the invention back in 1980, Prof. Baliga talked about how, while working at the General Electrical R&D centre in New York, he came up with the IGBT, which switches energy hundreds of thousands of times a second, resulting in a multifold increase in the efficiency of all digital equipment and computer hardware. Today, The IGBT is extensively used in the consumer, industrial, lighting, transportation, medical, renewable energy, and other sectors of the economy. It has enabled enormous reduction of gasoline and electrical energy use, resulting in huge cost savings to consumers, and reduction of worldwide carbon dioxide emissions.

He discussed various aspects of the invention emphasizing how, in the last 25 years, IGBTs have saved over 73,000 TWh of energy, over 1,48 trillion gas gallons, and have also decreased CO2 emissions by 49. 5 billion metric tons, with customers’ savings having exceeded $23.7 trillion. Moreover, the IGBT can be said to have saved around $24 trillion by raising the efficiency of such equipment. Every motor today is at least 40% more efficient, the CFL is 75% better and a motor vehicle saves over 10% fuel because of this invention. It is not for nothing that Prof. Baliga has been called the man with the largest negative carbon footprint in the world!

Jayant Baliga, here being given the National Medal of Technology and Innovation by President Obama, has saved the planet 100 trillion pounds of carbon emissions. (JIM WATSON/AFP/Getty Images)
Jayant Baliga, here being given the National Medal of Technology and Innovation by President Obama, has saved the planet 100 trillion pounds of carbon emissions. (JIM WATSON/AFP/Getty Images)

In between his busy schedule, he spoke to T5E about his career and work. You can also read a previous interview of Prof. Baliga by T5E’s Nithyanand Rao here.

IGBTs have become indispensable and ubiquitous today. Was the discovery of the IGBT in terms of today’s applications more by chance, which was then applied to all these industries, or was it more need-driven?

It was very application driven, and that is one of the main advantages of working with a very large and vertically integrated company like GE. By vertically integrated, I mean that not only do they build consumer electronics and aircraft engines, but also the necessary components for these products rather than relying on sourcing this technology from other firms. When I was working in GE in the 1980s, one of the engineers who wanted to build an adjustable speed drive was having trouble doing it with a simple bipolar transistor. So, he came to the research lab I was working at, and said that he desperately needed something better. It just so happened that I had been doing a lot of thinking on this problem already, and I told the management that my idea could not only be used for his application but also in many other fields.

So, it was not like “Oh we have a device, let’s see where can it be used”. Instead, this incident acted as the trigger for taking it from the idea stage to the product stage in a record ten months. After this incident, people discussed about even more uses of IGBT on their own. I was asked to give a presentation to the management discussing the complete idea and its applications across the verticals of GE like lighting, appliance controls, medical systems and so on. At the time, GE’s new Chairman, Jack Welch, was very young. The engineer who had approached me initially told the Chairman my idea; it’s very rare in a company of GE’s size for a research idea from a young scientist to reach the ears of the Chairman of the company. Because he wanted to create this business, he tried his best to impress Mr Welch with the help of this technology. There is seldom such a technology with such a wide-ranging application spectrum. So Mr. Welch said, “Okay, this is so important for my company, I better find out what this is”, and flew down from Connecticut to New York to meet me and learn about IGBT.

It was daunting back then, especially with a lot of critics at my heels. But he liked my presentation and affirmed support to my project and that was very very important in commercialising the technology. But, nothing was ready then. I had to design it, figure out the process of production, how to stop the latch out problem and control the speed, all within ten months. As soon as it was over, people were coming back to me and saying, “Look, we made this iron-box using your IGBT”, and I would be amazed at how quickly it was adapted by everyone. So, it was very much directed towards applications, and in an industry environment, that is what made it successful so fast. Also, it helped that I was smart enough to make it work the first time without failure, because critics were just waiting for me to stumble on the way.

The story of the development of the IGBT involves a lot of competing research labs. Could you give us a historical and factual context to this story?

Any great idea is always pursued by multiple people and groups at the same time. In such a competitive corporate world, it is really a race against time when people are filing patents or disclosing their inventions. In my case, I developed the IGBT very early, but Jack Welch said that this is so valuable to GE that we would like to keep it to ourselves and not show it to our competitors. So, I was not allowed to talk about it for several years, and people were led to believe that I didn’t do it until much later because I couldn’t take credit for it. But there is a lot of internal documentation to show that I was the first to work on it. In fact, the Inventor’s Hall of Fame inducted me as the sole inventor of IGBTs, and they are extremely selective in the patents they choose. Only 500 out of 9 million patents have been selected so far, and I am in the company of Henry Ford, Wright Brothers and Edison. I am thankful that even though I was not allowed to publish my work, I was recognised for it. GE gave me the Coolidge Award in 1983, the highest honour given to a scientist at GE, at the age of 35, while my contemporaries were on an average 20 years older. So, recognition came in different ways, and I am happy about it.

You have been conferred with innumerable top honors and awards. Of the numerous accolades credited to your name, is there any one which you hold special?

The most recent one of course, when I was inducted into the Inventor’s Hall of Fame and they declared me as the man with the ‘largest negative carbon footprint’ due to the impact of IGBTs on the energy systems and power electronics. Each of these are special in their own right. This latest one credits me as the sole inventor of IGBTs, and hence it is special.

For a layman, it was semiconductors then, and internet now. They have become a phenomenon which changed the world so fast and so much. What do you think is next?

There is so much going on right now. Especially in predictive healthcare. I see a good amount of research going on in that field by collecting data from every individual and taking preemptive measures towards maintaining the health of the individual. Talking about semiconductors itself, I am working on a second revolutionary idea which I theoretically proved 35 years back by Baliga’s Figure of Merit, but am getting to work on it only now. In MOSFET(metal oxide semiconductor field effect transistor) instead of using silicon, if we use silicon carbide or gallium arsenide, the resistance at high voltages reduces a lot (by 1000 times) and we get better performance in orders of magnitude if we compare to IGBT. This allows us to create a wide band gap switch and manifolds the benefits of IGBT. You can understand the physics of these materials by reading the literature; it is the next big quantum leap.

IGBTs are at the core of smart grids technology. But surely, there are many other challenges that they face. We see only a modicum of development on that front in India as well as the USA. What is stopping us?

Utilities are very slow in making changes, because it requires a huge investment which can only be made once the technology is proven to be very robust and mature. In a smart grid, power might flow two ways, and that means money will also have to flow two ways, and that is a very dicey thing. So, once the technology becomes more reliable, hopefully, there will be a natural push from utilities and consumers, and especially the government elected by these consumers. It will require a good amount of policy work from the government in order to protect the interests of consumers against the utilities.

You have worked in diverse roles. In the industry as a scientist and then leading a team of 40, in the academia and then as an entrepreneur, setting up 4 companies. What aspects stand out in each of these roles? And what was the reason behind a shift from GE to academia?

As a young scientist just out of his PhD, the GE research centre was an amazing place to start working. That was where I did most of my work on IGBTs. But unfortunately, we were not producing at costs competitive with the Japanese companies like Mitsubishi, Toshiba etc. The Japanese heard about my work and started manufacturing it at very low costs. So, Welch felt that it made more sense to import these components from them rather than producing them in-house. He had also invested a lot of money in CMOS, which was draining a lot of money. In a fit, he decided to sell all of the semiconductor business even though we showed that power is doing well enough. So, the whole vertical was shut down. But at that time, I was already the most highly honoured scientist at GE, and they didn’t want to throw me out. They started training me for a management role and I could have charted a completely different career trajectory from there on, somewhat similar to Welch himself and run business units and make a lot of money. The other option was to go to academia and educate students, and I chose that path because I was earning enough for myself and my list of needs did not have a yacht or such fancy items. You can say that I am a terrible businessman, not knowing how to make money. But I am a satisfied man in academia.

Finally, could you share with us some of your fondest memories of IIT Madras?

IIT is a phenomenal place to give you a foundation, where you are given a broad coverage of topics in every branch. Back in my time, there were no electives, and every batch had to go through a compulsory set of courses. But they were so chosen that we received an all-round training in materials, electronics, maths, physics, chemistry, etc. And this really helps when you work in research by enabling you to think in an interdisciplinary way. So, this helped me a lot when I went to the US.

Fondness comes to different people in different ways, but to me, the value this place holds is the great education that I received here and helped me be successful in the future. Of course when I graduated, IIT Madras was not this well known, as we were just the 6th passing out batch with no established alumni to speak of. I even had trouble getting financial aid while pursuing my graduate studies and there was a lot of apprehension about my abilities in coping up with the academic rigours in the USA. I ended up proving them wrong by scoring a perfect 4.0 GPA and getting the best PhD medal, but today, it is a different story. IITs are well recognised and respected. Why is that? Because a lot of students from the first few batches went abroad and broke open the barriers for the coming batches. This is quite crucial and the scenario could have been quite different, had we not done well as students over there. But, IIT Madras is always a special place and it has helped me a lot. To give back to it, I have donated it to the institute to give scholarships to students from the money I received along with the Global Energy Prize and other such prizes.

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