Introducing Spontaneously Phase‐Separated Heterogeneous Interfaces Enables Low Power Consumption and High Reliability for Phase Change Memory

Abstract

Phase‐change memory is one of the most promising candidates for the next generation nonvolatile memory, but their high power consumption and low reliability remain bottleneck problems that limit the data storage density and its storage‐class memory application. Here, an innovative phase change material with embedded self‐precipitated interfaces, where the nanoscale grains of phase change material are cut into interconnecting “crystal islands” by thermally stable self‐precipitated material with low thermal conductivity, is proposed. The precipitated material provides both thermal and atomic migration confinements in three dimensions. The thermal confinement enables low power consumption, and the atomic migration confinement enables high device reliability. The devices based on spontaneously phase‐separated O‐doped Sb2Te3 verify the material design, where Sb oxide acts as the precipitated heterogeneous phase and Sb–Te alloy as the phase change material. O‐doped Sb2Te3 device with 250 nm hole diameter shows an ultralow power consumption, down to a few hundreds of femtojoule, which is comparable with those of phase change nanowires. Besides, good thermal stability and low resistivity drift (drift coefficient 0.005) as well as excellent cycle endurance up to 108 times are also obtained at the same time. The doping fabrication process is quite compatible with current semiconductor industry.

A Fast and High Endurance Phase Change Memory Based on In-Doped Sb2Te3

“…Phase change random access memory (PCRAM) combines the advantages of nonvolatility and fast operation speed, thereby hopefully eliminating the distinction between data storage and memory. − The phase change material (PCM) glass’s extreme fragilityin which the atomic dynamics’ temperature dependence significantly deviates from Arrhenius behaviorensures quick and reversible phase transitions between crystalline and amorphous states when temperature changes . The sharp resistance differential between the crystalline phase of PCM, or low-resistance state, and the amorphous phase, or high-resistance state, which correspond to logic levels “0” and “1,” respectively, is used to encode digital information. , In recent years, the PCRAM based on ternary Ge 2 Sb 2 Te 5 was released into the memory market as a storage-class memory, such as the Optane memory, which fills the performance gap between DRAMs and FLASHs .…”