Moore’s law is not dead

Breakthrough at Lawrence Berkeley Labs proves possibility of one-nanometer nanotube gates.

Moore’s Law may burn out silicon as a platform, but the concept of ever shrinking transistors will live on, at least it will in Lawrence Berkeley Labs. Those geniuses at LBLN (Berkeley Lab), where they deal on a daily basis with stuff we can’t hardly even imagine, let alone see, have successfully fabricated the first transistor with a working 1 nm gate. Until now, a transistor gate size less than 5 nanometers has been considered impossible because of quantum tunneling effects. (FYI—one nanometer is the diameter of a glucose molecule.)

Schematic of a transistor with molybdenum disulfide semiconductor and 1-nanometer carbon nanotube gate. (credit: Sujay Desai/Berkeley Lab)
Schematic of a transistor with molybdenum disulfide semiconductor and 1-nanometer carbon nanotube gate. (Source: Sujay Desai/Berkeley Labs)

According to the Berkeley Lab news site, the team led by faculty scientist Ali Javey were able to create a 2D semiconductor field-effect transistor using molybdenum disulfide (MoS2) instead of silicon and a 1D single-walled carbon nanotube (SWCNT) as a gate electrode, instead of various metals. (SWCNTs are hollow cylindrical tubes with diameters as small as 1 nanometer.)

Using MoS2 instead of Silicon helps combat the tunneling effect that happens with gate lengths below 5 nanometers. Electrons flowing through silicon are are lighter and there is less resistance and at less than 5 nanometers  the electrons are able to break through the gate between the source and the drain terminals and the transistor can’t be turned off. In contrast electrons flowing through MoS2 are heavier so their flow is more easily controlled even at smaller gate lengths.

In addition, says the site Molybdenum disulfide can be scaled down to 0.64 nanometers —  atomically thin sheets, with a larger band gap and lower dielectric constant, a measure reflecting the ability of a material to store energy in an electric field (similar to a capacitor). These properties further enhance the ability to controle the flow of current in the transistor at small gate lengths. In this case to 1 nanometer.

The findings appeared in the Oct. 7 issue of the journal Science. Researchers at the University of Texas at Dallas, Stanford University, and the University of California, Berkeley, were also involved. The work at Berkeley Lab was primarily funded by the Department of Energy’s Basic Energy Sciences program.

According to an earlier article in CTimes on Sept. 30, TSMC said the company is working toward a 1-nanometer manufacturing process, starting with a “5 nanometers process technology, while putting about 300 to 400 R&D personnel in developing more advanced 3-nanometer process.” However, TSMC spokesperson Elizabeth Sun told KurzweilAI that “no further information regarding any technology either under development or in path-finding stage will be disclosed to the public at this point.”

At the 50th anniversary celebration of Moore’s Law in San Francisco, Gordon Moore confessed his surprise that it has held up as long as it has. He marveled that some new advance always seems to come along and save it and here we are again.

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