Press Release:

HP Announces Breakthroughs in Molecular Electronics

HP (NYSE: HPQ) today announced dramatic new breakthroughs in molecular electronics by scientists in HP Labs, the company's central research facility.

Speaking at a symposium celebrating the 175th anniversary of the Royal Institute of Technology of Sweden, R. Stanley Williams, HP Fellow and director of Quantum Science Research at HP Labs, said his group had:

  • created the highest density electronically addressable memory reported to date. The laboratory demonstration circuit, a 64-bit memory using molecular switches as active devices, fits inside a square micron -- an area so tiny that more than 1,000 of these circuits could fit on the end of a single strand of a human hair. The bit density of the device is more than 10 times greater than today's silicon memory chips;
  • combined, for the first time, both memory and logic using rewritable, non-volatile molecular-switch devices; and
  • fabricated the circuits using an advanced system of manufacturing called nano-imprint lithography -- essentially a printing method that allows an entire wafer of circuits to be stamped out quickly and inexpensively from a master.
"We believe molecular electronics will push advances in future computer technology far beyond the limits of silicon," said Williams. "Capacity and performance could be extended enormously by layering molecular-switch devices on conventional silicon without the need for complex and expensive changes to the base technology."

The circuits were fabricated using HP's patented cross-bar architecture incorporating molecular switches.

First, researchers made a master mold of eight parallel lines, each only 40 nanometers wide. Then, in a three-step process, researchers:

  1. Pressed the mold into a polymer layer on a silicon wafer to make eight parallel "east-west" trenches, which they then filled with platinum metal to form wires;
  2. Deposited a single layer of electronically switchable molecules on the surface; and
  3. Repeated the first step, after rotating the mold 90 degrees to make another eight wires, running "north-south," on top of the molecular layer.
At each of the 64 points where the top and bottom wires crossed, the roughly 1,000 molecules sandwiched between them became a bit of memory. A bit can be written by applying a voltage pulse to set the molecules' electrical resistance and read by measuring their resistance at a lower voltage.

"Using a combination of optical and electron beam lithography, it took about a day to create the master, which included 625 separate memories connected to conventional wires so that we can communicate with them," said Williams. "After that, it took just a few minutes to make an imprint."

The memories also proved to be both rewritable and non-volatile -- that is, they preserved information stored in them after the voltage was removed. Today's DRAM chips do not have this capability.

The researchers also put logic in the same circuit by configuring molecular-switch junctions to make a demultiplexer -- a logic circuit that uses a small number of wires to address memory. A demultiplexer is essential to make memories practical.

"This is the first demonstration that molecular logic and memory can work together on the same nanoscale circuits," said Williams.

Four U.S. patents have been awarded in connection with this work and scientific papers are being submitted to reviewed technical journals for publication.

The HP Labs research team that fabricated and tested the memory was led by senior scientist Yong Chen and included Douglas A. A. Ohlberg, Xuema Li, Duncan Stewart, Tan Ha, Gun-Young Jung and Hylke Wiersma.

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About HP

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