Princeton, HP Labs create plastic write-once memory

  • Tom Krazit (IDG News Service)
  • 14 November, 2003 08:09

A combination of a plastic material and a thin film of silicon has been demonstrated by researchers at Princeton University and Hewlett-Packard (HP) as an inexpensive method of storing digital information.

Researchers at the Princeton, New Jersey school and HP were able to develop a write-once memory cell that can hold gigabytes of information and be produced very inexpensively from a commonly used plastic substance and a small amount of silicon, they said.

The findings were first published in Thursday's edition of Nature magazine.

The plastic polymer is known as PEDOT, a shortened version of the chemical name for the substance. PEDOT conducts electricity at low voltages, but is a semiconductor at higher voltages, said Craig Perlov, a scientist with HP Labs, in an interview with the IDG News Service.

The scientists added fuses to the material, and when a high voltage is applied to certain areas on the material, a permanent trail of blown fuses and unblown fuses is left behind. The blown fuses could represent digital "zeros" and the unblown fuses digital "ones," allowing the device to store bits of data.

"The object is to make a device which is used in the same way flash memory is used in digital cameras and MP3 players," Perlov said. Flash memory, like PEDOT-based memory, is nonvolatile, which means it can store information without the constant electrical charge required by RAM in PCs, he said.

Users, however, would not be willing to pay as much for memory, like PEDOT-based memory, that can only be written to one time. But the inexpensive nature of the materials and development process would allow companies to charge less for the material, Perlov said.

Manufacturers would also be able to create extremely small storage devices with PEDOT because there are no moving parts in the material, the researchers said. A memory cube could be formed from small slivers of the PEDOT material, and the researchers envision being able to pack 1G byte of information into one cubic centimeter, they said.

Over time, the researchers expect to figure out a way to create rewritable memory from the substances, said Warren Jackson , an HP Labs scientist.

Modern semiconductors are processed from silicon wafers and need to go through a complicated process before emerging as finished products. The team thinks of the PEDOT memory cells as rolling off a press, almost like a sheet of plastic wrapping used in the kitchen, Perlov said.

The material could be used for other applications outside of memory chips, Jackson said. Retailers have expressed interest in RFID (radio frequency identification) tags as replacements for the bar code inventory system, but the cost of producing enough silicon-based chips for each item sold is staggering.

The PEDOT material has much more storage capacity than is required by an RFID chip, but it could be used to help identify and track goods in a warehouse or retail outlet, Jackson said.