The transistor of 2047: expert predictions

The 100th anniversary of the invention of the transistor will happen in 2047. What will transistors look like then? Will they even be the critical computing element they are today? IEEE spectrum asked experts from around the world for their predictions.

What will transistors look like in 2047?

Expect transistors to be even more varied than they are today, says one expert. Just as processors have evolved from CPUs to GPUs, network processors, AI accelerators and other specialized computer chips, transistors will evolve to serve different purposes. “Device technology is becoming application domain specific in the same way that computer architecture has become application domain specific,” says H.-S. Philip Wong, an IEEE Fellow, professor of electrical engineering at Stanford University and former vice president of business research at TSMC.

Despite the variety, the fundamental operating principle — the field effect that turns transistors on and off — will likely remain the same, suggests Suman Datta, an IEEE Fellow, professor of electricity and computing at Georgia Tech, and director of the multi-university nanotech research center ASCENT. This device likely has minimum critical dimensions of 1 nanometer or less, enabling device densities of 10 trillion per square centimeter, said Tsu-Jae King Liu, an IEEE Fellow, dean of the college of engineering at the University of California, Berkeley, and a member of the board of directors of Intel.

“It is safe to assume that the transistor or switch architectures of 2047 have already been demonstrated on a lab scale” -Sri Samavedam

Experts seem to agree that the 2047 transistor will require new materials and likely a stacked or 3D architecture, building on the planned complementary field effect transistor (CFET, or 3D stacked CMOS). [For more on the CFET, see “Taking Moore’s Law to New Heights.”] And the transistor channel, now parallel to the plane of the silicon, may need to become vertical to keep increasing in density, Datta says.

AMD senior fellow Richard Schultz suggests that the main goal in developing these new devices will be power. “The focus will be on reducing power and the need for advanced cooling solutions,” he says. “Considerable attention to devices operating at lower voltages is required.”

Will transistors still be the heart of most computers in 25 years?

It’s hard to imagine a world where computing isn’t done with transistors, but of course vacuum tubes were once the digital switch of choice. According to McKinsey & Co. start-up funding for quantum computing, which does not rely directly on transistors, will reach $1.4 billion by 2021.

But advances in quantum computing won’t happen fast enough to challenge the transistor by 2047, electron device experts say. “Transistors will continue to be the most important computing element,” said Sayeef Salahuddin, an IEEE Fellow and professor of electrical engineering and computer science at the University of California, Berkeley. “Currently, the potential fields of application, even with an ideal quantum computer, seem rather limited compared to classical computers.”

Sri Samavedam, senior vice president of CMOS technologies at European chip R&D center Imec, agrees. “Transistors will continue to be very important computing elements for most general purpose computing applications,” says Samavedam. “One cannot ignore the realized efficiencies of decades of continuous transistor optimization.”

Has the transistor of 2047 already been invented?

Twenty-five years is a long time, but in the world of semiconductor R&D, it’s not that long. “In this industry it usually takes about 20 years [demonstrating a concept] to introduction into production,” says Samavedam. “It’s safe to assume that the transistor or switch architectures of 2047 have already been demonstrated on a lab scale,” even though the materials involved won’t be exactly the same. King Liu, who demonstrated the modern FinFET with colleagues at Berkeley some 25 years ago, agrees.

But the idea that the transistor of 2047 is already in a lab somewhere is not shared by everyone. For example, Salahuddin thinks it hasn’t been invented yet. “But like the FinFET in the 1990s, it is possible to make a reasonable prediction for the geometric structure” of future transistors, he says.

AMD’s Schultz says you can glimpse this structure in proposed 3D stacked devices made from 2D semiconductors or carbon-based semiconductors. “Device materials that have not yet been invented may also be within range in this time frame,” he adds.

Will silicon still be the active part of most transistors in 2047?

Experts say that the heart of most devices, the transistor channel region, will still be silicon, or possibly silicon-germanium – which is already making its way – or germanium. But in 2047, many chips may use semiconductors that are considered exotic today. These can be oxide semiconductors such as indium gallium zinc oxide; 2D semiconductors, such as the metal dichalcogenide tungsten disulfide; and one-dimensional semiconductors, such as carbon nanotubes. Or even ‘others yet to be invented’, says Imec’s Samavedam.

“Transistors will remain the most important element of computation” – Sayeef Salahuddin

Silicon-based chips can be integrated into the same package with chips that rely on newer materials, just as processor manufacturers today integrate chips using different silicon manufacturing technologies into the same package, notes IEEE Fellow Gabriel Loh, a senior fellow at AMD.

Which semiconductor material forms the core of the device may not even be the central issue in 2047. “The choice of channel material will essentially be determined by which material is most compatible with many other materials that make up other parts of the device.” says Salahuddin. And we know a lot about integrating materials with silicon.

In 2047, where will transistors be common where they are not found now?

Everywhere. No seriously. Experts really expect a certain amount of intelligence and feeling to creep into every aspect of our lives. That means devices are attached to our bodies and implanted in them; embedded in all kinds of infrastructure, including roads, walls and houses; woven into our clothes; stuck to our food; swaying in the wind in wheat fields; looking at just about every step in every supply chain; and do many other things in places no one has thought of yet.

Transistors will be “wherever computation, command and control, communication, data collection, storage and analysis, intelligence, sensing and activation, interaction with humans or a gateway to the virtual and mixed reality world are needed,” lists Stanford’s Wong.

This article appears in the December 2022 print issue as “The Transistor of 2047”.

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