Flipped transistors make fleeter computer chips | Science
Things are looking up for transistors. Researchers from IBM and Samsung have made the first prototype computer chip in which the transistors stand on their ends, a change that will make it possible to pack circuitry more tightly and enable faster or more energy-efficient devices.
“It’s a major breakthrough,” says Dan Hutcheson, a semiconductor industry analyst with TechInsights. “It gives us an idea of what the next generation of devices will look like.”
Since the first integrated circuits were built in the 1960s, semiconductor companies have designed transistors to lie flat on silicon chips, with electrical current moving laterally through them. They’ve also managed to shrink successive generations of transistors ever smaller. This trend, known as Moore’s law, has allowed companies to double the number of transistors on chips every 2 years. Chips headed for manufacturing plants in the next few years will cram a staggering 50 billion transistors into a space the size of a fingernail.
But Moore’s law is headed for a breakdown. Transistors consist of several separate electrical conductors designed to control the flow of current through a semiconductor. Smush those components closer together than about 45 nanometers, or 45 billionths of 1 meter, and current starts to leak from one to the next. At that point, the transistors no longer function. “We needed to find another solution,” says Brent Anderson, an IBM engineer who led the vertical transistor project.
That solution was to stand the transistors on end, like a brick balanced on one end. That enabled researchers to keep the length of individual devices large enough to function perfectly, while jamming them together more tightly than 45 nanometers apart.
At the International Electron Devices Meeting in San Francisco on Saturday, Anderson and his colleagues reported creating a dinner plate–size silicon wafer packed with vertical transistors. Though the researchers didn’t specify all the steps needed to fabricate it, Anderson’s colleague Hemanth Jagannathan says they were able to do so largely using standard semiconducting manufacturing tools. That’s critical because semiconductor fabrication facilities cost billions of dollars to set up. “We don’t make any drastic changes unless we need to,” Jagannathan says.
The advance should sustain Moore’s law for another decade or so, Hutcheson predicts. Packing in more transistors will enable future chip designers to design processors that either run twice as fast or reduce their energy to just 15% of today’s standard. The energy savings could, for example, make future cellphones that can operate for up to 1 week without charging.