The vertically connected layers may increase the speed and the number of transistors in a computer chip. The result is multiple layers of transistors with extremely short connections, and hence, faster and denser circuits, says Gerold Neudeck, a professor of electrical and computer engineering who co-wrote a paper about the work that appeared in June in a scientific journal.
Faster circuits lead to computers with higher performance.
Denser circuits help decrease the cost of chips by increasing the number that can be manufactured in a given area. To grow the silicon into precisely placed islands, Neudeck first etches holes into silicon dioxide with hydrofluoric acid and then fills the holes with silicon by using a well-known process called chemical vapor deposition. Such precise structuring is not possible with conventional technology, in which silicon is deposited as a blanket onto the surface of a wafer and then formed into islands during numerous steps such as chemical etching. The Purdue method builds the islands automatically, skipping about 10 of the first 32 steps now required to make conventional chips. A major potential benefit of the technology is that there is theoretically no limit to the number of layers that could be stacked, offering the possibility of making more complex circuits in less space, thus increasing the performance of computer chips.