Phase transition kinetics and microstructures of AgInSbTe ͑AIST͒ and AIST-SiO 2 nanocomposite applied to phase-change memories ͑PCMs͒ are investigated. In situ electrical property measurement found that the incorporation of SiO 2 escalates the recrystallization temperature ͑T x ͒ of nanocomposite. Both X-ray diffraction and transmission electron microscopy showed grain refinement in the nanocomposite which, in turn, results in an increase of the activation energy ͑E a ͒ of phase transition, as indicated by subsequent Kissinger's analysis. Increase of T x and E a in the nanocomposite was ascribed to AIST grain refinement and hindrance to grain growth due to dispersed SiO 2 particles in the sample matrix. Johnson-Mehl-Avrami analysis revealed the decrease of Avrami exponent in nanocomposite, implying that the dispersed SiO 2 particles promote the heterogeneous phase transition. Static I-V characteristics and reversible binary switching behavior of PCM devices not only confirmed the results of microstructure characterizations but also illustrated the feasibility of the AIST and its nanocomposite layer for PCM fabrication.Phase-change memory ͑PCM͒ has been recognized as nextgeneration nonvolatile memory device due to its advantages, including good scalability, high operation speed, low power consumption, high recording density, signal endurance, etc. 1-9 Instead of using laser beam as the heating source in optical data storage, PCM devices utilize a current pulse to heat the phase-change programming layer embedded in devices for signal recording. In order to reduce operating current of PCM devices, various methods have been proposed. One is to define a smaller programming volume by modifying the PCM cell structure, while the other is to modify the physical properties of phase-change materials by, for instance, increasing the resistivity of the phase-change layer in the crystalline state by doping a small amount of nitrogen ͑N͒, 1,2 oxygen ͑O͒, 3,4 silicon ͑Si͒, 5,6 silicon oxide ͑SiO x ͒, 7-9 etc.In contrast to the nucleation-dominated GeSbTe ͑GST͒ alloys, binary Sb 2 Te alloys are termed as the growth-dominated chalcogenides. 10 In practice, Sb 2 Te alloys are usually doped with desired elements for physical property improvement. 11 The Sb 2 Te alloys doped with silver ͑Ag͒ and indium ͑In͒, i.e., the quaternary AgInSbTe ͑AIST͒, are known to possess better cycling stability of amorphous phase and higher crystallization sensitivity in comparison with other phase-change materials. 12,13 Further, the study on digital versatile disk containing AIST illustrated that the disk possesses high recording density and data-transfer rate features. 14 Good optical properties imply that AIST might also be a promising material for PCM application. However, the electrical properties of AIST are less reported and a further study to identify its feasibility to PCM is required.Previous studies reported that incorporating SiO 2 in GST may effectively improve the stability of amorphous GST and reduce the reset current of PCM devices. 8,9 ...
