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from the breaking-the-thermionic-limit dept.
Purdue University researchers have demonstrated a transistor using a negative capacitor made with hafnium zirconium oxide:
Researchers have experimentally demonstrated how to harness a property called negative capacitance for a new type of transistor that could reduce power consumption, validating a theory proposed in 2008 by a team at Purdue University.
[...] Capacitance, or the storage of electrical charge, normally has a positive value. However, using the ferroelectric material in a transistor's gate allows for negative capacitance, which could result in far lower power consumption to operate a transistor. Such an innovation could bring more efficient devices that run longer on a battery charge.
[...] Properly switching off [transistors] is of special importance to ensure that no electricity "leaks" through. This switching normally requires a minimum of 60 millivolts for every tenfold increase in current, a requirement called the thermionic limit. However, transistors that harness negative capacitance might break this fundamental limit, switching at far lower voltages and resulting in less power consumption.
Steep-slope hysteresis-free negative capacitance MoS2 transistors (DOI: 10.1038/s41565-017-0010-1) (DX)
2014: Negative capacitance in a ferroelectric capacitor (DOI: 10.1038/nmat4148) (DX)
2008: Use of Negative Capacitance to Provide Voltage Amplification for Low Power Nanoscale Devices (DOI: 10.1021/nl071804g) (DX)
(Score: 2, Informative) by Anonymous Coward on Thursday December 21 2017, @07:55AM
Very low, because the size of the structures inside CPUs and such is so small that any radio signal you will encounter will have a wavelength of many times the feature size, which makes the feature a very bad antenna for that signal. A 1/4 lambda for a 1 THz signal is 75um, which is pretty huge for modern semiconductor technology, and 1THz is very high for external interference.
60mV is a lot; I've build DC/DC converters with current measurement signals in that range, and then you're talking about opamps, comparators, and traces on a PCB, right next to power MOSFETs switching tens or in some cases even hundreds of amps. That 60mV would be the entire signal range, the desired resolution and accuracy are in the order of 100uV. Some applications, like instrumentation amplifiers for strain gauges and such, work with even smaller signals, but they generally are separated and shielded from noise sources as much as possible.