Material science. A pathbreaking semiconductor technology that looks beyond silicon

For long, semiconductors have been associated with silicon, even though silicon is just one of a handful of semiconductors. But now, a challenger has emerged.

Bengaluru-based NexGen Power Systems has achieved success with gallium nitride (GaN), a material that offers several significant advantages over silicon. To name two, the GaN chips can be “95 per cent smaller” than a silicon chip of the same functionality, while also being more energy efficient. For example, a 1,200 V device working on 30 amp current would be 30 sq mm with silicon; with GaN, it would be just 2 sq mm.

“It is not like others haven’t been working on GaN,” says Dinesh Ramanathan, one of the founders and co-CEO of NexGen, but with a decade of research the founders have figured out how to use the material. The company has 105 patents, with applications for 30 more pending.

So, the science was already known, but NexGen worked it into a technology. The company was founded in 2017 by Ramanathan and a group of investors led by Ahmad Chatila, the former founder of the solar energy developer SunEdison. Chatila’s investment arm Fenice Investment Group has parented several companies in India in the recent past, including NexGen and the electrolyser manufacturer Ohmium.

NexGen, which recently raised an undisclosed sum from a group of investors, has 20 people in its Bengaluru office and this number will rise five-fold soon.

Ramanathan calls GaN “the biggest revolution in power electronics in 30 years”. At the heart of the technology is the concept called ‘bandgap energy’, which is the energy required by the outermost electrons of an atom to jump out of the atom. GaN’s bandgap energy is more than three times that of silicon, which means it is three times more stable. Power electronics made with GaN, therefore, can work in high-temperature conditions, such as in automobiles. GaN has “extremely high breakdown voltage”, which means it takes only a tiny amount of GaN to withstand very high voltages. Typically, in silicon-based power electronics, if you want to operate at high voltage, you need to make it bigger; but with GaN you don’t, Ramanathan told Quantum .

Previously, users of GaN typically tried to gum GaN on top of silicon, but Ramanathan says this is not a good idea for several technical reasons. NexGen’s proprietary technology makes an all-GaN device possible. The trick, and the challenge, was to design an “architecture that is cost-effective, high in performance and easily manufacturable,” says Ramanathan.

The company uses a leased fab in Syracuse, New York, to make the semiconductors, while the design and worldwide marketing is done out of Bengaluru.

India is a big market. Ramanathan says the company expects to get customers from LED, electric vehicles and data centre segments. Another round of fund-raise has been indicated.

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