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The single layer Zn 44 Sb 39 Se 17 thin film, being fabricated by Sb 70 Se 30 and Zn using co-sputtering method, exhibits double phase change transition. The double phase change processes are mainly attributed to the crystallization of the Sb and ZnSb phases. The potential operating temperature for ten years of two phase change processes are 64 °C and 179 °C, of which the good stability of the second phase change can be sufficient for the autoelectronic applications. Meanwhile we also discovered the Zn 44 Sb 39 Se 17 thin film presents apparent low power consumption in comparison with Ge 2 Sb 2 Te 5 and other reported Sb-Se based phase change materials. Image, graphical abstract [ABSTRACT FROM AUTHOR]

Abstract Phase change materials along the GeTe-Sb isoelectronic tie line are proved to be promising host material for optimization, based on which the well-known golden composition is developed. Here, Sc doped Ge 2 Sb 1 Te 2 has been proposed for phase change memory (PCM) application, showing higher thermal stability and faster operation speed than those of the golden composition. The fast speed of 40 ns, high 10-year data retention of 160 °C, and good endurance of 6×105 cycles have made Sc 0.2 Ge 2 Sb 1 Te 2 a promising candidate for PCM application. The impact of Sc on the microstructure is believed to be essential for those improvements in PCM. [ABSTRACT FROM AUTHOR]

Abstract The phase change memory with Al-Sb-Ge alloy is investigated for the feasibility of embedded system and the potential possibility of multilevel data storage. The Al 15 Sb 53 Ge 32 compound has a high crystallization temperature (333 °C) and outstanding data retention ability (260 °C). Ge atoms inhibit crystal growth to enhance thermal stability and Al 15 Sb 53 Ge 32 contains sequential crystallization of Sb-rich and Ge regions in two-step crystallization process. Remarkably, the device presents a fast speed of 50 ns and endurance up to 2.3 × 104 cycles. At the same time, a reliable tripe-level resistance state of the phase change memory cell is observed. Graphical abstract The phase change memory with Al-Sb-Ge alloy is investigated for the feasibility of embedded system and the potential possibility of multilevel data storage. Compared with conventional CGST, the selected composition of Al 15 Sb 53 Ge 32 has a higher crystallization temperature and an outstanding 10-year data retention temperature, especially maintains the fast operation speed in devices. Besides, the thickness variation between amorphous and crystalline states is distinctly reduced below 3.6% prolonging the lifetime of a PCM device. TEM results prove that the grain growth is suppressed by Ge atoms, resulting in good thermal stability. Moreover, the sequential crystallization of Sb-rich and Ge regions may be advantageously used for multilevel data storage. For PCM cells based on Al 15 Sb 53 Ge 32 material, a fast speed of 50 ns and a high endurance of more than 2.3 × 104 are all demonstrated to be realized and a reliable tripe-level resistance state of the phase change memory cell is observed. Unlabelled Image [ABSTRACT FROM AUTHOR]

After compositing with Si, the superlattice-like (SLL) Si/Sb thin film had higher crystallization temperature (~ 231 °C), larger crystallization activation energy (2.95 eV), and better data retention ability (126 °C for 10 years). The crystallization of Sb in SLL Si/Sb thin films was restrained by the multilayer interfaces. The reversible resistance transition could be achieved by an electric pulse as short as 10 ns for [Si(22 nm)/Sb(2 nm)] 2 -based PCM cell. A lower operation power consumption of 0.02 mW and a good endurance of 1.0 × 10 5 cycles were achieved. In addition, SLL [Si(22 nm)/Sb(2 nm)] 2 thin film showed a low thermal conductivity of 0.11 W/(m·K). [ABSTRACT FROM AUTHOR]

Compared with Sb 2 Se, Si–Sb–Se material is proved to be a promising candidate for phase change memory (PCM) use because of its higher crystallization temperature (~ 230 °C), larger crystallization activation energy (3.25 eV), and better data retention ability (168 °C for 10 years). Furthermore, the fast crystallization time 3.30 ns is obtained for Si 0.20 (Sb 2 Se) 0.80 material by the picosecond laser technique. The set switching is realized with low threshold current 6.9 μA and voltage 1.80 V, respectively. The reverse resistance transition can be achieved by an electric pulse as short as 8 ns for Si 0.20 (Sb 2 Se) 0.80 -based PCM cell. [ABSTRACT FROM AUTHOR]

The amorphous-to-crystalline transitions of superlattice-like Ge 8 Sb 92 /Ge thin films were investigated through in situ film resistance measurement. X-ray reflectivity was used to measure the density change before and after phase change. The superlattice-like structure of the thin films was confirmed by using transmission electron microscopy. A picosecond laser pump–probe system was used to study the phase change speed. Phase change memory cells based on the SLL [Ge 8 Sb 92 (4 nm)/Ge(3 nm)] 7 thin films were fabricated to test and verify the switching speed and operation consumption. [ABSTRACT FROM AUTHOR]

We investigate the statistics of the crystallization kinetics caused by the finite size of nanoscale samples. We define a characteristic length, L C, as a function of the material properties, in order to describe the sample size dependence of the statistics. We find that the samples smaller than L C undergo single-nucleus crystallization, which yields wide distributions of the half-transition time. Finally, we apply our theory to find a way to improve the data retention statistics of sub-20nm phase-change memory. [ABSTRACT FROM AUTHOR]

In comparison to Sb2Se, Al19Sb54Se27 has a higher crystallization temperature, larger crystallization activation energy, better data retention and a wider energy band gap. X-ray diffractometry and X-ray photoelectron spectroscopy were employed to study the crystalline structure and chemical bonding state, respectively, of the elements in Al19Sb54Se27. The picosecond laser technique was used to measure the phase-change time of Al19Sb54Se27. Phase-change memory devices based on Al19Sb54Se27 thin films were fabricated to test and evaluate their electrical properties. [ABSTRACT FROM AUTHOR]

The crystallization temperatures and 10year data retention temperatures of the Sb80Te20/SbSe nanocomposite multilayer films can be modulated by varying the thickness ratio between Sb80Te20 and SbSe layers. The crystallization dynamics of the films induced by nanosecond laser pulses are studied using in situ reflectivity measurement. The set and reset operation for phase change memory device based on [Sb80Te20 (4nm)/SbSe (10nm)]7 multilayer film can be achieved by an electric pulse as short as 50ns. [ABSTRACT FROM AUTHOR]

The crystallization temperature of superlattice-like GaSb/Sb2Te3 films can be easily changed by the number of interfaces and thickness ratio between GaSb and Sb2Te3 layers. The reset operation can be completed by an electric pulse as short as 20ns for the GaSb(4nm)/Sb2Te3(6nm)-based phase-change memory test cell. This test cell exhibited endurance up to 1.4×104 cycles. The thermal simulation confirmed that the improved performance of superlattice-like GaSb/Sb2Te3 films originated from the low thermal conductivity and low melting point. [ABSTRACT FROM AUTHOR]

The crystallization temperature of GeTe film increases markedly from 187 to 372°C as a result of 9.81at.% nitrogen doping, and a rhombohedral–rocksalt phase transition is observed in both GeTe and nitrogen-doped GeTe (GeTeN) films. Up to 105 cycles of endurance for phase change memory (PCM) cells based on GeTeN have been achieved. Extrafine data retention (10years at 241°C) and relatively low power consumption suggest GeTeN as a promising alternative material to improve the performance of PCM. [ABSTRACT FROM AUTHOR]