You may be aware of Moore’s law in computer technology. The number of transistors on a microchip has been doubling about every 18 months. In 1970 there were several thousand transistors on a chip. In 2020 “we” reached 50 billion! One great driver is shrinking the size of the individual transistor. One old chips you can see the key part, the gate between the source and the drain. On the latest commercial chips in laptops the width of the gate is as small at 2 nm. That’s about 40,000 times less than the width of a human hair. Minuscule size brings problems of leakage from what’s called quantum tunneling. Mehrdad Kiani and Judy Cha point to another problem. Transistors and other elements need connections of ordinary conductors. Aluminum metal and then copper became the choice for the connectors. However, as the connectors get smaller they increase in electrical resistance and could dramatically slow the computer operation. New metals called topological semimetals are in development. They have modes of conducting electrical currents that are protected by quantum effects from developing high resistance at small size. We’ll be seeing perhaps molybdenum phosphide or the like. The new materials have to be proven stable against moving or corroding. It will be interesting.
Source: Science, 6 Nov. 2025, pp. 572-3.
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This has been an outreach activity of the Las Cruces Academy, viewable at GreatSchools.org
