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What will transistors look like in 2047?

Expect transistors to be even more diverse than they are now, says one expert. As processors have evolved from CPUs to include GPUs, network processors, AI accelerators, and other specialized computing chips, transistors will evolve to fit different purposes. “Device technology will become application domain-specific in the same way that computing architectures have become application domain-specific,” says H.-S. Philip Wong, an IEEE Fellow, professor of electrical engineering at Stanford University and former vice president of corporate research at TSMC.

Despite the differences, the basic operating principle — field effects that turn transistors on and off — will likely remain the same, suggests Suman Dutta, an IEEE Fellow, professor of electrical and computer science at Georgia Tech and director of the multi-university nanotech research center ASCENT. The device will likely have critical dimensions of at least 1 nanometer or less, enabling a density of 10 trillion devices 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 Intel’s board of directors. .

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

Experts seem to agree that the 2047’s transistors will require new materials and possibly a stacked or 3D architecture, expanding on the proposed complementary field-effect transistor (CFET, or 3D-stacked CMOS). [For more on the CFET, see “Taking Moore’s Law to New Heights.”] And transistor channels, which now run parallel to the plane of the silicon, may need to be vertical to continue increasing density, Dutta said.

AMD Senior Fellow Richard Schultz suggests that power will be a key focus in developing these new devices. “Focus will require power reduction and improved cooling solutions,” he says. “Significant focus is needed on devices that operate at lower voltages.”

Will the transistor still be the heart of most computing 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. Startup funding for quantum computing, which does not rely directly on transistors, will reach $1.4 billion in 2021, according to McKinsey & Co.

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

Agrees Sri Samvedam, senior vice president of CMOS technology at European chip R&D center Imec. “Transistors will still be very important computing components for most general-purpose computing applications,” Sambedam said. “One cannot ignore the efficiencies realized from decades of continuous optimization of transistors.”

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 introduce manufacturing,” said Samvedam. “It is safe to assume that transistor or switch architectures of 2047 have already been demonstrated on a lab scale” even if the materials involved are not exactly the same. King Liu, who demonstrated modern FinFETs with colleagues at Berkeley nearly 25 years ago, agrees.

But the idea that the transistor of 2047 is already sitting in a lab somewhere is not universally shared. Salahuddin, for one, doesn’t think it’s invented yet. “But as with the FinFET of 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 see this structure in proposed 3D-stacked devices made of 2D semiconductors or carbon-based semiconductors. “Device materials that haven’t been invented yet can also be in this timeframe,” he added.

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 perhaps silicon-germanium—which is already making inroads—or germanium. But many chips in 2047 may use semiconductors that are considered exotic today. These may include oxide semiconductors such as indium gallium zinc oxide; 2D semiconductors, such as metal dichalcogenide tungsten disulfide; and one-dimensional semiconductors, such as carbon nanotubes. Or even “others yet to be invented,” says Emek’s Samvedam.

“Transistors will remain the most important computing component” – Saif Salahuddin

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

A semiconductor component at the heart of a device may not even be a central issue in 2047 “The choice of channel material will largely be dictated by which material is most compatible with the other components that make up the other parts of the device,” Salahuddin said. And we know a lot about combining materials with silicon.

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

Seriously not everywhere. Experts really expect some degree of intelligence and sensitivity in every aspect of our lives. That means the devices will be attached to our bodies and implanted inside them; embedded in all types of infrastructure, including roads, walls and houses; woven into our clothing; stuck to our diet; The wind sways in the fields; Watching almost every step in every supply chain; And no one has yet thought of doing much else in such a place

Stanford’s Wang summarizes “transistors will be everywhere that need a gateway portal to the worlds of computation, command and control, communication, data collection, storage and analysis, intelligence, sensing and actuation, human interaction, or virtual and mixed reality.”

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