“We believe we have a practical, comprehensive strategy for moving computing beyond silicon to the world of molecular-scale electronics,” says Stan Williams, senior fellow and director, Quantum Science Research (QSR), HP Labs.
“We have a three-pronged approach: fundamental scientific research into the quantum effects that dominate the nanometer scale, a new architecture that can tolerate defects in molecular-sized circuit components and cost-effective methods of fabrication.”
The HP vision is based on its patented crossbar architecture - one set of parallel nanowires running approximately perpendicular to another set, sandwiching a thin layer of an electrically switchable material.
Every intersection of wires can then form an electrical switch, which could be programmed to configure the crossbar to perform various functions, such as store a bit or perform a logic operation.
The crossbar architecture is potentially easier and less expensive to manufacture than conventional silicon technology, according to HP, because it doesn’t require the same level of mechanical precision and is well-suited to tolerate the inevitable defects that are bound to occur in the fabrication process at such tiny dimensions.
QSR is also looking at fundamental science underlying computing at the molecular scale. “At the nano level, quantum mechanics takes over from classical physics - electrons behave more like waves than particles. We are studying how we can use quantum properties to enable new functions in a circuit,” says Williams.
QSR researchers are examining the properties of various metals for wires and materials for switches that could be used in fabrication at the nano level. They are also proposing ways in which nano devices could be linked to conventional microelectronics.
They are also looking at a variety of fabrication processes, from nano-imprint lithography to chemical self-assembly by growing silicon nanowires between electrodes.