Theoretical explanation of different crystallization processes between as-deposited and melt-quenched amorphous Ge2Sb2Te5 thin films

Temperature dependence of thermal properties of Ag8In14Sb55Te23 phase-change memory materials

“…Chalcongenide phase-change materials are extensively used as the optical and nonvolatile electrical data storage media due to the apparent difference in optical reflectivity and electrical resistivity between the crystalline and amorphous state [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. For optical data storage, the recording is achieved by forming amorphous marks on a crystalline base with a focused laser beam.…”

“…When the laser beam is switched off, the melted marks quench into an amorphous state due to the high thermal conductivity of the substrate underneath the phase-change materials. Conversely, the recorded marks are erased when the materials are heated above the glass transition temperature but yet below the melting threshold so that the materials return to the crystalline state [7][8][9][10][11][12][13][14][15][16][17]. For the nonvolatile electrical storage, applying a higher voltage pulse (reset pulse) to the crystalline state with low resistivity leads to the local melting and consequently the formation of an amorphous information bit with high resistivity due to the rapid quenching.…”

“…With the development of the phase-change memory, various materials were examined, and the materials of the best performances in terms of speed and stability were found to be GeSbTe (abbreviated as GST) family, such as Ge 2 Sb 2 Te 5 and Ge 1 Sb 4 Te 7 [4,9,16,17,[21][22][23], and AgInSbTe (abbreviated as AIST) family, such as Ag 3.4 [2,3,7,[11][12][13][14][15][24][25][26][27][28]. The thermal properties of GST family were measured and studied in details, and the studies showed that there were common characteristics for different members in the GST family due to the distorted NaCl-type rock structures [21,22].…”

Time Resolved Investigation of Fast Phase- Change Phenomena in Rewritable Optical Recording Media

“…In contrast to the reliability and high-speed-performance of DVD media, the mechanism of rapid phase change, especially crystallization from the amorphous phase is still not fully understood, in spite of a lot of investigation using transmission electron microscopy (Park et al, 1999;Naito et al, 2004), fluctuation electron microscopy (Kwon et al, 2007), optical (Wei & Gan, 2003), electronic (Lee et al, 2005), and structural (Yamada & Matsunaga, 2000;Kolobov et al, 2004;Kohara et al, 2006) studies. We therefore developed the X-ray pinpoint structural measurement system , which enables the 40 picosecond time resolved pump and probe X-ray diffraction experiment using 100 nm scale SR beam.…”

Pulsed-laser deposited amorphous-like PZT thin-films: Microstructure and optical properties

“…On the other hand, in various new material groups, like rare-earth transition-metal bulk metallic glasses (BMG), some pseudobinary alloy systems, and shape-memory alloys, for example, the phase transformation between amorphous and crystalline state can be controlled by heat or light to generate memory effect based on change of magnetic or optical properties. [1][2][3][4] Conventionally crystalline functional BaTiO 3 and Pb(Zr x Ti 1−x )O 3 ceramics have also been successfully prepared in the amorphous form in a way preserving their ferroelectricity. 5 Throughout the literature it is frequently brought up that the phenomena affecting in the early stages of formation of crystalline structure are not fully understood.…”