A new material helps transistors become vanishingly small | Hacker News Reader

A new material helps transistors become vanishingly small

economist.com

80 pointsprostoalex10 comments

Another article on the topic: https://techxplore.com/news/2020-06-amorphous-boron-nitride-...

https://nanohub.org/resources/18349/download/NikonovBeyondCM...

Has nice models and details on post cmos, for the curious. The papers (nikonov and young) are excellent, though I think they underrate the back end scaling challenges.

This is about replacing the low k dielectric in the backend, and makes sense if you consider that backend metal will move to W or Co. so long as this is CMP capable (maybe?) this makes sense.

https://archive.is/O9fBP

BN looks interesting, but it doesn't matter how good an insulator is if, in use, its thickness approaches the wavelength of your charge carrier, enough so to tunnel through easily. For reference, the wavelength of an electron "at rest" is ~0.1 nm, but QM rarely conforms to simple arithmetical intuition.

My expectations for continuation of Moore's law are pinned, possibly too optimistically, on spintronics.

I became fascinated with spintronics for about a year. Somewhat unrelated, but perhaps interesting to some readers, is that you can create spin-LEDs. If you use a material to permit only electrons of a certain spin (spin-up or spin-down) to transport to the excitation layer of the LED, the resultant emitted photons will be helically polarized. Fascinating stuff.

Interesting, is that what is used for stereoscopic video screens?

Good question, but I'm 99.9999% sure no. They may us Circularly Polarized light (I actually don't know), but if they do it's made by filtration of unpolarized light rather than polarized electroluminescence. When I was researching the topic (~2008-ish), Spin-LEDs were largely still in the lab - a lot of work at Stanford spintronics lab as I recall. At that time, they were able to achieve a strong bias of circularly polarized light. I just googled it and apparently there's beed good progress in 'purifying' the polarization handedness [1]. If you can harness CP emission, it opens the door for many very interesting applications. CP light is fascinating.

1. https://www.spiedigitallibrary.org/conference-proceedings-of...

Very cool, thanks for answer and the paper link!

> if, in use, its thickness approaches the wavelength of your charge carrier

Tangentially, a conceptually similar and equally counterintuitive phenomenon is attenuated total reflection. (https://en.wikipedia.org/wiki/Attenuated_total_reflectance)

Fascinating.

I had only just learned about "evanescent wave" interactions. The idea is that, alongside wave propagation, E-M mechanics admits numerous non-wave, and therefore short-range solutions. These solutions are necessary to explain total internal reflection. E-M interactions with materials a short distance beyond the boundary can change the reflectance. ATR is clever in using multiple such interactions to sample properties of a material close enough to the boundary.

Reply on news.ycombinator.com