That's a really interesting question. I think there's no real problem, because the sorts of materials in those capacitors can easily withstand much larger forces.
I bet the Casimir calculation is done assuming there's a vacuum between the plates. It's not hard to calculate the attractive force due to, say, a 3V potential on the capacitor with 10 nm plate separation. It would be somewhat larger than the force from the Casimir effect. Inclusion of a dielectric material would increase the ordinary electrical force on the plates, for a given voltage. I'm not sure how it would affect the Casimir force.
In general you're right, however, that special finite-size quantum effects are becoming important in nanoelectronics. Also simple statistical fluctuations in the number of charge carriers become important in small transistors, etc.
Mike W.
(published on 06/26/2008)
