If by 'geometries' you mean 'scale', then no, that hasn't been the case for like 5 or 10 years. It's called nanotechnology (a subfield of materials science). I'm majoring in it. It's very interesting and useful.
Look at graphene: http://images.iop.org/dl/physicsweb/2010/phwv19i11a34.pdf
I wasn't talking about nanotechnology, I was talking about conventional lithographic integrated circuits, which is what flash is so far as I know. So feature size is limited to the current process, something like .28 nm at the moment, but obviously they can still use the tunneling effect. That may have something to do with the thickness of vapor deposition, don't know.