Nanowire transistor escapes the Boltzmann tyranny

The traditional workhorse of digital computing is running on its last legs. In the age of AI, we need smaller and more energy-efficient transistors more than ever, but two issues stand in the way. One is the so-called subthreshold swing, or the increase in the gate-to-source voltage needed to boost the on-current tenfold. Also known as the Boltzmann tyranny, it’s limited to 60 millivolts per decade at best, imposing a fundamental lower limit on the operating voltage of CMOS and hence on the minimum energy required per CMOS calculation.

Short-channel effects are another major roadblock. This collection of performance-degrading phenomena, which include current leakage in the off-state and lowered carrier mobility, can occur when the gate length is small compared to the combined size of the source and drain. This necessitates a minimum gate length and therefore presents a lower limit to the transistor footprint.