The thermal stability of amorphous Sb₂Te film can be significantly improved by the addition of Cu. CuSb₄Te₂ alloy is considered to be a potential candidate for phase change random access memory (PCRAM), as evidenced by a higher crystallization temperature, a better data retention ability, and a faster switching speed in comparison with those of Ge₂Sb₂Te₅. A reversible switching between set and reset states can be realized by an electric pulse as short as 7 ns for CuSb₄Te₂-based PCRAM cell. In addition, CuSb₄Te₂ shows endurance up to 1.5 × 10⁵ cycles with a resistance ratio of about two orders of magnitude.

Phase-change memory (PCM) has considerable promise for new applications based on von Neumann and emerging neuromorphic computing systems. However, a key challenge in harnessing the advantages of PCM devices is achieving high-speed operation of these devices at elevated temperatures, which is critical for the efficient processing and reliable storage of data at full capacity. Herein, we report a novel PCM device based on Ta-doped antimony telluride (Sb₂Te), which exhibits both high-speed characteristics and excellent high-temperature characteristics, with an operation speed of 2 ns, endurance of > 10⁶ cycles, and reversible switching at 140 °C. The high coordination number of Ta and the strong bonds between Ta and Sb/Te atoms contribute to the robustness of the amorphous structure, which improves the thermal stability. Furthermore, the small grains in the three-dimensional limit lead to an increased energy efficiency and a reduced risk of layer segregation, reducing the power consumption and improving the long-term endurance. Our findings for this new Ta–Sb₂Te material system can facilitate the development of PCMs with improved performance and novel applications.

In this paper, Te-free Ga-Sb-Se material is considered to be a storage medium for phase change memory. Compared with Ge₂Sb₂Te₅, Ga₁Sb₆Se₃ exhibits a better thermal stability, which leads to a brilliant performance for data retention. Ga₁Sb₆Se₃-based phase change memory cell shows reversible switching between reset and set states with a resistance ratio of two orders of magnitude. The minimum reset/set voltages are significantly lower than those of Ge₂Sb₂Te₅-based one. Meanwhile, Ga₁Sb₆Se₃ film possesses a faster switching speed than Ge₂Sb₂Te₅. Thermal simulation confirms the improvement of cell performance originating from the low thermal conductivity and low melting point of Ga₁Sb₆Se₃.

Phase‐change memory (PCM) has been developed for three‐dimensional (3D) data storage devices, posing huge challenges to the thermal stability and reliability of PCM. However, the low thermal stability of Ge₂Sb₂Te₅ (GST) limits further application. Here, we demonstrate PCM based on In_0.9Ge₂Sb₂Te₅ (IGST) alloy, showing 180°C 10‐years data retention, 6 ns set speed, one order of magnitude longer life time, and 75% reduced power consumption compared to GST‐based device. The In can occupy the cationic positions and the In‐Te octahedrons with good phase‐change properties can geometrically match well with the host Ge‐Te and Sb‐Te octahedrons, acting as nucleation centers to boost the set speed and enhance the endurance of IGST device. Introducing stable matched phase‐change octahedrons can be a feasible way to achieve practical PCMs. image

In order to improve the electrical performance of resistive random access memory (RRAM), sulfur (S)-doping technology for HfOx-based RRAM is systematically investigated in this paper. HfOx films with different S-doping contents are achieved by atmospheric pressure chemical vapor deposition (APCVD) under a series of preparation temperatures. The effect of S on crystallinity, surface topography, element composition of HfOx thin films and resistive switching (RS) performance of HfOx-based devices are discussed. Compared with an undoped device, the V_SET/V_RESET of the S-doped device with optimal S content (~1.66 At.%) is reduced, and the compliance current (Icc) is limited from 1 mA to 100 μA. Moreover, it also has high uniformity of resistance and voltage, stable endurance, good retention characteristics, fast response speed (SET 6.25 μs/RESET 7.50 μs) and low energy consumption (SET 9.08 nJ/RESET 6.72 nJ). Based on X-ray photoelectron spectroscopy (XPS) data and fitting of the high/low resistance state (HRS/LRS) conduction behavior, a switching mechanism is considered to explain the formation and rupture of conductive filaments (CFs) composed of oxygen vacancies in undoped and S-doped HfOx-based devices. Doping by sulfur is proposed to introduce the appropriate concentration oxygen vacancies into HfOx film and suppress the random formation of CFs in HfOx-based device, and thus improve the performance of the TiN/HfOx/ITO device.