Beyond silicon?
Xerox Says New Material Will Allow Plastic Transistors
By JOHN MARKOFF
Xerox technologist will describe a new material today that allows the creation of "printed" plastic transistors, which the company says could one day make possible inexpensive, lightweight and flexible displays for cellphones, laptops and televisions.
The advance will be detailed in a paper to be presented at the Materials Research Conference in Boston by Beng Ong, a research fellow at Xerox Research Center of Canada in Mississauga, Ontario. He will describe an experimental polymer that can be used to make organic transistors on a plastic substrate.
"We believe polymers will be much easier and lower cost to manufacture," said Tony Paine, an executive at Xerox's innovation group in Toronto. He said that a near-term commercial application for the new material could be in the manufacturing of the transistors that serve as the drivers for liquid crystal displays, like those used in phones and personal digital assistants, or P.D.A.'s.
"Think about the value of a laptop or cellphone display that you could drop without breaking," said Raj Apte, a member of the research staff at Xerox's Palo Alto Research Center. "Making a cellphone or a P.D.A. that you could sit on is a no-brainer."
The new material is promising, Xerox researchers said yesterday, because it will potentially have the electronic properties of silicon while also being slow to degrade in the presence of oxygen. Earlier organic semiconductors were impractical because they decayed when exposed to air.
The material, polythiophene, has achieved performance on electronics benchmarks that is an order of magnitude greater than current polymer materials.
Xerox researchers said the company envisioned a new electronics manufacturing process on roll-to-roll machinery, which is now used in publishing and in the manufacturing of solar cells. Under a grant from the National Institute for Standards and Technology, the Palo Alto Research Center is experimenting with Dow Chemical and Motorola to create a manufacturing process based on roll-to-roll material handling and depositing that would form the polymer material into circuit patterns using ink jets.
Currently, silicon-based microelectronic devices are made using a photo-lithographic manufacturing process that involves depositing and chemically etching materials on a rigid silicon substrate.
Other researchers in the field said plastic semiconductors that could be printed in high volume and low cost were a hot area for research and commercial activity.
"I'm aware of six or eight companies trying to make these transistors," said Dr. Michael D. McCreary, vice president for research and development at E Ink, a display manufacturer in Cambridge, Mass. He said that his company planned to commercialize its first display next year and that it had created a prototype plastic display in partnership with Lucent Technologies.
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