ELECTRONICS M
any advances in digital electronics are strongly linked toMoore’s law: examples are quality-adjustedmicroprocessor prices,memory capacity, sensors and even the number and size of pixels in
digital cameras. But can this continue indefinitely? Intel stated in
2015 that the pace of advancement has slowed, starting at the 22nmfeature width around 2012, and continuing at 14nm.However, in April 2016, Intel CEO Brian Krzanich stated: “Inmy 34 years in the semiconductor industry, I have witnessed the advertised death ofMoore’s Law no less than four times. As we progress from14nmtechnology to 10nmand plan for 7nmand 5nmand even beyond, our plans are proof thatMoore’s Law is alive and well.” Silicon-based technologies have nearly reached
the physical limits of the number and size of transistors that can be crammed into one chip, while alternative technologies are still far frommass implementation. Down-scaling transistor size is more than an engineering challenge, as there is fundamental physics to consider. So overall, perpetuatingMoore’s Law in the
foreseeable future will require disruptive technologies which take the electronics industry beyond its silicon comfort zone.Whether these can be developed in time forMoore’s Law to be maintained in the immediate future is touch and go, but even if not, there is no reason why it could not resume in the future. “The whole semiconductor industry wants to keep
Moore’s Law going.We need better performing transistors as we continue down-scaling, and transistors based on silicon won’t give us improvements anymore,” saysHeinz Schmid, a researcher with IBMResearch GmbHat Zurich Research Laboratory in Switzerland. Schmid’s teamwith support fromcolleagues in
YorktownHeights, New York has developed a relatively simple, robust and versatile process for growing crystalsmade fromcompound semiconductormaterials that will allow themto be integrated onto silicon wafers – an important step towardmaking future computer chips that will allow integrated circuits to continue shrinking in size and cost even as they increase in performance. The IBMteamhas fabricated single crystal
nanostructures, such as nanowires, nanostructures containing constrictions, and cross junctions, as well as 3-D stacked nanowires,made with so-called III–
Vmaterials.Made fromalloys of indium, galliumand arsenide, III-V semiconductors are seen as a possible futurematerial for computer chips, but only if they can be successfully integrated onto silicon. So far efforts at integration have not been very successful. “What sets this work apart fromothermethods is
that the compound semiconductor does not contain detrimental defects, and that the process is fully compatible with current chip fabrication technology,” says Schmid. “Importantly themethod is also economically viable.”
48 /// Environmental Engineering /// April 2017
Moore’s law – the observation that the number of transistors in a dense integrated circuit doubles approximately every 18-24 months – is a projection and not a physical or natural law. Andy Pye looks at some of the disruptive technologies which aim to ensure it can continue
Touch and go for Moore?
Polariton fluid emits clockwise or anticlockwise spin light by applying electric fields to a semiconductor chip
ZERO RESISTANCE MATERIALS Asminiaturisation progresses, power becomes critically important: how to reduce power flowing through electronic components? Related to this is the amount of heat generated during operation. While atomic andmolecular sizes cannot be
changed, the heat problemis not unsolvable. Recent research has shown that in two-dimensional systems, including semiconductors, electrical resistance decreases and can reach almost zero when they are subjected tomagnetic andmicrowave influence. There are several differentmodels and
explanations for the zero-resistance phenomenon in these systems.However, the scientific community has not reached an agreement on thismatter because semiconductors used in electronics are complex and processes in themare difficult tomodel mathematically. An example is research conducted by the
QuantumDynamics Unit at Okinawa Institute of Science and Technology Graduate University (OIST), which could represent an important step in understanding two-dimensional semiconductors. The Unit is researching anomalies in the behaviour of electrons in a liquid heliumtwo-dimensional system. The systemismaintained at a temperature close
to absolute zero (-272.75ºC or 0.4K) to keep the heliumliquefied. Conditions are similar to those that led to observations of zero resistance in semiconductors.
PICTURE: ALEXANDER DREISMANN
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