Researchers at IBM came up with a new method to let molecules assemble themselves inside chip structures to form nanoscale structures. IBM demonstrated this technique, in which ordinary industrial polymer is applied to an ordinary silicon wafer. Then it is heated to produce a crystalline structure that can store information.
The group used a material known as a diblock copolymer molecule in its research. This material is actually two molecules that naturally seek to repel each other under certain conditions, Black said. When a silicon wafer is heated, the polymer naturally forms crystal structures about 20 nanometers wide that can be used to store information within transistors, he said.
Chip makers have been building smaller and smaller transistors for years, but transistor sizes are approaching a critical limit in the next decade when the transistor's floating gate will become too small to hold a charge, and therefore store information, Black said. This technique provides a way to replace the floating gate with several nanocrystals allowed to self-assemble inside a transistor, he said.
Theoretically, the method could be used to build structures even smaller than 20 nanometers by using a smaller polymer, although nothing has been demonstrated as of yet, Black said.
In order to use this technique to build smaller integrated circuits, researchers will also need to discover a way to position the crystals in order to carry out specified functions, Black said. But for now, the nanocrystals can be used as memory devices, and IBM is working on methods to build circuits using self-assembly techniques, he said.
The primary benefit of this method is that the nanocrystal structures can be built using existing lithography methods and tools, without having to invest in costly new methods of production, Black said. IBM constructed the crystals on 200 millimeter wafers using existing process technologies, he said.