Bilayer Ga-Sb Phase Change Memory with Intermediate Resistance State

Among various phase-change memory materials (PCMs), Ge 2 Sb 2 Te 5 (GST) is an outstanding representative, widely used in both optical storage and electronic memories [1] . The intrinsic drawbacks of this GST, however, such as tellurium volatility and low amorphous phase stability (resistance retention), hinder it from being a perfect candidate. Tellurium-free antimony-based PCMs have been the subject of considerable recent interest, due to their excellent resistance contrast, rapid crystallization, and high amorphous phase stability [2] . Moreover, with increasing demand for high-capacity memory in consumer electronics, the multibit high-density storage capability of various memory devices has become very attractive [3] – [5] . Here, a bilayer Ga-Sb stack structure is demonstrated, showing multilevel switching properties. The origin of multilevel states and their stability are also studied.