University of Cambridge researchers have developed phase-change materials (PCMs)-based devices that can be melted and recrystallized in as little as half a nanosecond using appropriate voltage pulses. The researchers say the technology could lead to the next generation of faster, smaller, more energy-efficient computers. "As demand for faster computers continues to increase, we are rapidly reaching the limits of silicon's capabilities," says Cambridge professor Stephen Elliott. One strategy for increasing processing speed without increasing the number of logic devices is to increase the number of calculations each device can perform, which is not possible using silicon. However, the Cambridge researchers have demonstrated that multiple calculations are possible for PCM devices. The researchers found that by performing the logic-operation process in reverse, the materials are both much more stable and capable of performing operations much faster. The intrinsic switching speed of existing PCMs is about 10 nanoseconds, making them suitable for replacing flash memory. If the speeds can be increased further, they could replace a computer's dynamic random-access memory (DRAM) with a non-volatile PCM device. "Eventually, what we really want to do is to replace both DRAM and logic processors in computers by new PCM-based non-volatile devices," Elliott says.
