Until we develop advanced nanotechnology for atomically precise manufacturing, the use of nanotech molecular devices in computing will be limited by the ability to interface with conventional microtechnology. In a step toward use of molecular electronics in practical computing devices, researchers have assembled molecular films on the Si(100) surface utilized in conventional CMOS technologies and shown them to be of comparable quality to those assembled in earlier studies on the Si(111) surface, which is not compatible with CMOS. From “NIST team proves bridge from conventional to molecular electronics possible“
Researchers at the National Institute of Standards and Technology (NIST) have set the stage for building the “evolutionary link” between the microelectronics of today built from semiconductor compounds and future generations of devices made largely from complex organic molecules. In an upcoming paper [abstract] in the Journal of the American Chemical Society, a NIST team demonstrates that a single layer of organic molecules can be assembled on the same sort of substrate used in conventional microchips.
The ability to use a silicon crystal substrate that is compatible with the industry-standard CMOS (complementary metal oxide semiconductor) manufacturing technology paves the way for hybrid CMOS-molecular device circuitry—the necessary precursor to a “beyond CMOS” totally molecular technology—to be fabricated in the near future.
Scientists classify crystal structures by the particular plane or “face” cutting through the crystal that is exposed. Most research to date on silicon substrates for molecular electronic devices has been done with a crystal orientation that is convenient for organic molecules but incompatible with CMOS technologies. For their electronic device, the NIST team first demonstrated that a good quality monolayer of organic molecules could be assembled on the silicon orientation common to industrial CMOS fabrication, verifying this with extensive spectroscopic analysis.
—Jim
