[dieselerator]

The research looks detailed and interesting. However, I don't follow this summary article.

Digital circuits dissipate most of the energy charging and discharging capacitance. It must necessarily dissipate that as heat (except for a minor amount of electro-magnetic radiation). The interconnect resistance hardly matters. Of course RC relay can be a factor for some circuits. We can hope this reasearch leads to improvement there.

Power supply bus resistance can lead to voltage drops, but this research apparently studies layers much too thin for that application.

Did I missing something?

[mystified5016]

The interconnect resistance does matter as resistance is a function of cross-sectional area. It's related to the physical size of the conductor. Lower resistance conductors can be physically smaller while carrying the same amount of current.

But the real trick is if you can increase your switching speed, you lose less energy in the transistor. All the time in between 0 and 1, the transistor is burning energy as heat rather than conducting current. Lower R in your interconnect means your RC time constant goes down and your switching speed goes up. Your transistor spends less time in the linear region and wastes less energy.

But yes, these are pretty small effects on the whole. That's really just where the industry is at: incremental improvements until the Next Big Thing comes along.

Additional nit: up to 50% of the energy put into gate capacitance could be recovered. It's not necessary to waste 100%, it's just dramatically cheaper and easier. Honestly I doubt there's any practical benefit as the chip would become quite a lot larger.

[rbanffy]

> Honestly I doubt there's any practical benefit as the chip would become quite a lot larger.

There will be at some point when area becomes too small to accommodate the heating and the added complexity becomes a way to shrink the entire chip to sizes that wouldn’t be possible otherwise.