Toward the Speed Limit of Phase Change Memory.

Phase change memory (PCM) is one of the most promising candidates for next-generation data-storage technology, the programming speed of which has enhanced within a timescale from milliseconds to subnanosecond (∼500 picoseconds) through decades of effort. As the potential applications of PCM strongly depend on the switching speed, namely, the time required for the recrystallization of amorphous chalcogenide media, the finding of the ultimate crystallization speed is of great importance both theoretically and practically. Here, through systematic analysis of discovered phase change materials and ab initio molecular dynamics simulations, we first predict elemental Sb-based PCM may have a superfast crystallization speed. Indeed, such cells experimentally present extremely fast crystallization speeds within 360 ps. Remarkably, the recrystallization process is further speeded up as the device shrinks, and a record fast crystallization speed of only 242 ps is achieved in 60 nm-size devices. These findings open opportunities for DRAM-like and even cache-like PCM using appropriate storage materials. This article is protected by copyright. All rights reserved.