After our recent story of Vertical Circuits, the small company attempting to build 3D flash memory chips, we have news of a bigger player taking the same approach to the imminent end of expanding storage capacities.

SanDisk CEO Eli Harari revealed this week that his firm is so concerned that it won't be able to keep making bigger flash storage it too is working on the 3D, or stacking, approach.

Head up

Speaking to the New York Times Harari explained: "When Manhattan ran out of space, they built skyscrapers. It's the same for us."

SanDisk is addressing the problem because of the immutable physical fact that its technique of using electrons to record data states is limited by the need to have at least one per data cell.

Five years left

When that lower limit is reached, there will be no way to increase capacity, as chip builders can't use zero electrons to do their sums. Hence, the tactic of stacking layers of chips atop each other.

Harari predicts single flash memory chips will top out at around 32GB within five years - that's just two or three more doublings of current capacities.

Healthy competition

To date, the company has managed to build 3D chips with up to eight layers, providing a theoretical maximum of 256GB some way down the road. However, the prototypes can still only be written to once.

Nevertheless, with several competitors vying for the lead in the 3D memory market the prospects for a commercial breakthrough before current techniques reach the end of the line look promising.