The general, perception appears to be that whatever “quantum” means, it represents 21^st Century revolutionary innovations shattering the laws of classical physics and moving us into entirely unchartered territories. The reality is that, as discussed in the blog #449, quantum phenomena (unraveled by Bohr, Heisenberg, Schrödinger, Einstein and others some 100 years ago, by the way), are present in semiconductor device engineering for quite some time already.

Quantum phenomena did not have any practical bearing until we’ve developed capability to process materials in a single nanometer (nm) range (as a reminder, size of an average atom is in the range of 0.2 – 0.3 nm)  Whether it is a 5 nm long transistor’s gate where ballistic transport can take over charge transport, 1.5 nm thick gate oxide, where quantum tunneling leakage current messes up transistors operation, or 10 nm thick epitaxial layer acting as a quantum well where 2DEG (two dimensional electron gas) control device performance, or smaller than 10 nm quantum dot where any change in the dots diameter affects its fundamental properties, there is no “quantum” without “nano”. In other words, if it not were for our aggressive scientific and engineering efforts over the last half a Century aimed at the reduction of geometry of transistors in cutting edge digital ICs to a single nanometer level (developing the tools and the methods of nanotechnology in the process), quantum physics would not be a part of functional semiconductor devices engineering and the concept of quantum transistor and then quantum computing would remain in the sphere of unattainable in practice goals. So, in short, “nano” is making “quantum” feasible.