SANTA CLARA, Calif. Nanotechnology will play a key role in next-generation silicon, and may help extend CMOS scaling down into the single-digit nanometer range, according to researchers at a DesignCon technology forum here. But technologies like carbon nanotubes, nanowires and single-electron transistors still aren't ready for prime time, they noted.
Nanotechnology isn't hype it's here right now, panelists said. At the 90-nm node, gate lengths are 50 nm, which is "clearly nanotechnology by any definition," said George Bourianoff, Intel Corp.'s senior program manager for the strategic research group at Intel.
Bourianoff said there's a "push-pull relationship" between the silicon industry and nanotechnology. He said carbon nanotubes and nanowires may extend CMOS scaling down to the 1 to 3 nm range. At the same time, he noted, the silicon manufacturing infrastructure is an ideal platform for enabling nanotechnology.
Promising technologies, according to Bourianoff, include crossed nanowire structures that form matrices, transistors that use a single electron to control current flow and carbon nanotubes. But more work is needed, he said. "The difficulty of carbon nanotube FETs is controlling the quality and getting adequate quantity," he said. "Even with their favorable properties, they're a long ways from manufacturing."
Molecular devices are another possibility, he said, although the maximum speed attained with devices thus far is 2 Hz. Researchers have proposed two-dimensional, self-assembled arrays made of nanoparticles laid on silicon substrates. Another concept uses a Buckyball molecule between source and drain to act as a channel.
There are also alternatives to the use of electric charge to store information, such as spin transistors or quantum computing. But all of the new technologies need more research before they come into practical use, Bourianoff said. He predicted that "radical" new nanotechnologies will emerge by 2020.
Daniel Gamota, manager for new products manufacturing at Motorola Inc., described his company's work with "printed organic electronics." Working with newspaper printers, and a former silkscreen T-shirt printer, Motorola has been able to print materials with embedded nanoparticles, he said.
"If we're successful, we might be able to print paper that changes color based on temperature or mood," he said. "Or we could print big-screen TVs." Gamota described an "organic FET" that's printed with suspended nanoparticles and nano-composite oxides.
But the challenge, he said, is getting nanotechnology into high-volume manufacturing. One thing that's needed, Gamota said, is standards for device performance, testing, specification, and manufacturing. The IEEE, he noted, has launched a standards effort for nanoelectronics.
IBM has applied a molecular "self-assembly" technique to nanotechnology, said Christie Marrian, manager of the nanoscale structures and devices group at IBM's Almaden Research Center. With self-assembly, components naturally place themselves into an ordered structure. IBM recently applied this technology to flash memory devices.
Marrian said a nanocrystal flash memory can provide better scalability, retention and lower voltage operation than conventional flash. With IBM's approach, silicon nanocrystal arrays are formed between the device polysilicon gate and silicon substrate, and are electrically isolated by control and program oxides.
"It looks like an extremely attractive way of making a flash device," Marrian said. Nanocrystal array formation, he noted, "is not perfect but is something we continue to work on."