Scientists explore the feasibility of replacing silicon with phase-change materials that can switch between crystalline and glass states.
Moore’s law is the prediction that the number of transistors in a dense integrated circuit will double approximately every two years. The principle is named after Gordon E. Moore, co-founder of the Intel Corporation. His prediction has remained accurate partly because the concept is used in the semiconductor industry to set targets for development. However, the industry is slowly approaching a plateau with silicon-based circuits, and with Moore’s law in peril, the search is on for the next computing substrate. Keeping up the pace of progress in an ever more computer and data driven world will likely require a post-silicon invention that can satisfy growing needs for faster, smaller and more powerful computers.
In recognition of the limitations of current computer technology, scientists from the University of Cambridge in England, the Singapore A*STAR Data-Storage Institute and the Singapore University of Technology and Design are exploring the feasibility of replacing silicon with a material that can switch back and forth between different electrical states. Phase-change materials (PCMs) can switch between two structural phases with different electrical states, one crystalline and conducting and the other glassy and insulating, in billionths of a second. It’s a technology that could one day enable processing speeds one-thousand times faster than current systems.
As described in the journal Proceedings of the National Academy of Sciences, the researchers created a PCM-based processor using chalcogenide glass, which can be melted and recrystallized in as little as half a nanosecond (one billionth of a second) when the correct voltage is applied. The team showed that logic-processing operations can be performed in non-volatile memory cells using combinations of ultra-short voltage pulses, which is not possible with silicon-based technology. This works because the PCM devices store logic operations and memory in the same location.
A major drawback of prototype PCM devices is that they are not as fast as their silicon-based counterparts. There is also a stability issue affecting the amorphous phase. But the researchers found that by performing logic operations in reverse, putting the crystalline phase first, they can facilitate faster, more stable performance.