When thinking about nanoelectronics, it is useful to remember 1941, when engineers worked on vacuum-tube computers to decode message traffic and compute trajectories. The ideas for solid-state devices were out there then – many of the basic patents were filed in the 1925-1930 period. But it would take until 1948 for Bell Labs researchers to unveil the transistor, one that passed muster on a key test: gain.
Logic depends on gain, which delivers the ability to drive a fanout. Being able to store a bit as a one or zero is nice: that is what memories do. (Nanoelectronics already has gone down two dead-ends because of this challenge: molecular devices which work fine as memories but have no gain, and single-electron transistors (SETs), which are difficult to combine into logic circuits.)
A charge-based logic device which exhibits gain comes at a price: heat.
Heat is what forced out vacuum tubes, heat is what relegated bipolar transistors to their niche, and heat now is challenging CMOS.
For the post-CMOS logic element, we are back in that 1941 frame of mind.
By about 2020, a new computational state element will be needed which moves beyond charge, and does so at very little heat. Initially, it must be able to be combined with conventional CMOS devices.
As Jeff Welser -- the director of the Nanoelectronics Research Initiative (NRI) at the Semiconductor Research Corporation (SRC) – points out, developing a new logic element is an endeavor that is so expensive and far out in the future that it requires a collective effort.
Using an electron’s spin as the computing state variable, rather than charge, is one field of study. Thus far, these quantum spin devices are in the realm of speculative physics rather than electronic engineering. While there are several good device proposals, there is “very little clear understanding” of what actually goes on at that level of matter, said Welser, adding that "the Holy Grail is to move a spin wave along a wire."
Intel’s director of technology strategy Paolo Gargini is optimistic. "Ideas for new transistors are out there, professors are working on them, and progress, however miniscule, is being achieved," said Gargini, who helped set up the NRI organization.
About weQuest: weQuest's are written by G Dan Hutcheson, his career spans more than thirty years, in which he became a well-known as a visionary for helping companies make businesses out of technology. This includes hundreds of successful programs involving product development, positioning, and launch in Semiconductor, Technology, Medicine, Energy, Business, High Tech, Enviorntment, Electronics, healthcare and Business devisions.