While the physics of conventional semiconductors only allow the size of transistor gates to be reduced to 5 nm, engineers at Lawrence Berkeley National Laboratory have developed a working transistor with a 1 nm gate. In comparison, a human hair is about 50,000 nanometers thick.
Javey, lead principal investigator of the Electronic Materials program in Berkeley Lab’s Materials Science Division commented, “We demonstrated a 1-nanometer-gate transistor, showing that with the choice of proper materials, there is a lot more room to shrink our electronics.”
The key was to use molybdenum disulfide (MoS2) and carbon nanotubes. The engineers published their findings in the journal Science.
The development could be key to temporarily reviving Intel co-founder Gordon Moore’s prediction that the density of transistors on integrated circuits would double every two years.
Transistors have three terminals: a source, a drain, and a gate. The gate controls the current that flows from the source to the drain. The gate switches on and off in response to applied voltage.
￼With conventional semiconductors below 5 nanometers, the phenomenon of tunneling begins in which the gate barrier can no longer keep the electrons from barging through between the source and the drain terminals. The ability to be made into thin sheets, the lower dielectric constant, and the greater mass of the electron compared to Silicon improve the control of the current flow inside the transistor when the gate length is reduced to 1 nanometer.
Once the engineers settled on MoS2 as the semiconductor material but they still need to fabricate the 1-nanometer structure. The researchers turned to carbon nanotubes because conventional lithography techniques don’t work well at that scale.
They measured the electrical properties of the devices to show that the MoS2 transistor with a carbon-nanotube gate can effectively control the flow of electrons.
Funding for this work came primarily from the Department of Energy’s Basic Energy Sciences program. The engineers conducted some of this research at the Molecular Foundry, a DOE Office of Science User Facility.