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This work presents the optimization of the crystallization behavior and reliability of Sn15Sb85 thin films by doping Sm element. The phase transition behaviors induced by thermal were investigated by in situ resistance measurement. With the addition of Sm element, Sn15Sb85 film exhibits the superior crystallization temperature (232 °C) and data conservation (172.32 °C for 10 years), larger activation energy of crystallization (4.91 eV) and crystalline resistance (∼103 Ω), which contributes to the increased thermal stability of the amorphous state and decrease in the programming energy. The Sm-doping can broaden the energy band gap from 0.55 to 1.07 eV. The amorphous Sm and Sn compositions could retard grain growth and refine grain size from 21.13 to 11.13 nm, combining with x-ray diffraction and x-ray photoelectron spectroscopy. The surface morphology of Sn15Sb85 film becomes smoother after Sm doping as determined by atomic force microscopy images, resulting in the improved interfacial reliability. Phase change memory devices based on Sm0.095(Sn15Sb85)0.905 films can successfully achieve the complete SET and RESET reversible operation process with high operating speed (200 ns) and low power consumption (1.6 × 10−10 J). The results suggest that doping the proper concentration of Sm element will be an effectual solution to adapt and optimize the crystallization properties of Sn15Sb85 phase change material. [ABSTRACT FROM AUTHOR]

Thermal stability and phase transition rate are two important issues that restrict the engineering applications of phase change memories. In this paper, GeSb/Sb multilayer films were prepared by multilayer stacking, and their phase transition properties were investigated. GeSb/Sb multilayer films had higher crystallization temperature, better data retention, and lower resistance drift than pure Sb films, which indicated that they had excellent thermal stability and accuracy of resistance identification. The test results of X‐ray diffraction and atomic force microscopy showed that GeSb spacer layers could inhibit grain growth of Sb film layers, thus reducing the roughness and potential fluctuation of the film surface. X‐ray reflectivity experiments showed that the GeSb/Sb multilayer films before and after crystallization had small volume changes. The devices based on [GeSb(7 nm)/Sb(3 nm)]8 multilayer films could achieve reversible resistive transition operation between SET and RESET at a pulse width of 10 ns, showing satisfactory transition rate and operational power consumption. The low resistance drift and ultra‐fast phase transition speed make GeSb/Sb multilayer films one of the promising choices for phase change memories. [ABSTRACT FROM AUTHOR]

The development of high-performance flexible memory materials is of great significance to today's rapidly growing Internet of Things market. In this paper, Ge2Sb2Te5 phase change films were prepared by magnetron sputtering on Si/SiO2 and flexible polyether-ether-ketone substrates. Their phase change properties were systematically investigated and compared. Their transitions from the amorphous to the crystalline state were compared using an in situ heating method. The effect of different bending radii and the number of bending cycles on the change in resistance was investigated. Changes in the energy band gap at different cycle times were measured by NIR spectrophotometry and changes in the phase structure of the samples after different cycle times were investigated by X-ray diffraction. The surface morphology of the films was observed by atomic force microscopy and scanning electron microscopy after different cycle times. Phase change memory devices based on polyether-ether-ketone substrates were prepared for the Ge2Sb2Te5 materials. The results showed that Ge2Sb2Te5 films based on polyether-ether-ketone substrates have excellent phase transition properties and the potential to become flexible memory devices. [ABSTRACT FROM AUTHOR]

Effects of the titanium dopant on the physical properties and structure of SbSe thin films were systematically investigated by experiments and first-principles calculations. The amorphous-to-polycrystalline transformation induced by heat was examined by in situ electrical resistance measurements. With the incorporation of titanium atoms, both the crystallization temperature and electrical resistance increase, revealing the improvement of the amorphous thermal stability and programing energy consumption. X-ray diffraction, transmission electron microscopy, and density functional theory calculations illustrate that a small amount of titanium dopant can inhibit the grain growth and refine the crystal size. The shift of Raman modes associated Sb upon the crystallization was observed. X-ray reflectivity and atomic force microscopy results prove the smaller volume fluctuation and the smoother surface morphology, meaning the better interfacial property and reliability of titanium-doped SbSe materials. Phase change memory cells based on titanium-doped antimony-selenium were fabricated to evaluate the electrical performance as well. All these results indicate that the suitable incorporation of the titanium element will be an effective method to optimize the physical properties and tune the structure of the SbSe phase change material. [ABSTRACT FROM AUTHOR]

Nitrogen doping is applied to improve the thermal stability and power consumption of SbSe phase change thin film. Comparing to un-doped SbSe thin film, N-doped SbSe thin film has a higher crystallization temperature and better data retention. The measurement of atomic force microscopy indicated that the crystallization is inhibited and the surface of thin films becomes smoother after N doping. The analysis of X-ray diffraction proved that nitrogen doping can suppress the grain growth of the films and limit the grain size. The phase transition speed between the amorphous and crystalline state was investigated by the picosecond laser pulses. Phase change memory devices based on N-doped thin films were fabricated to test and evaluate the electrical properties. The results indicate that nitrogen-doped SbSe films have the potential in phase change memory application. [ABSTRACT FROM AUTHOR]

Comparing to un-doped ZnSb material, N-doped ZnSb material had higher crystallization temperature, lower conductivity and better data retention. The optical band gap was derived from the transmittance spectra and a significant increase was observed with increasing nitrogen doping concentration. The measurement of atomic force microscopy indicated that the crystallization was inhibited and the surface of thin films became smoother after N doping. Phase change memory devices based on N-doped ZnSb thin film were fabricated to test and verify their electrical properties. [ABSTRACT FROM AUTHOR]

[Display omitted] • GeSb/HfO 2 superlattice-like films were prepared by magnetron sputtering. • The thermal stability of GeSb/HfO 2 is greatly improved. • Under the influence of HfO 2 , the grain size of the film decreases to 3.34 nm. • The density of the film decreased to 4.27% before and after phase transition. • The energy required for RESET operation of Ge 1 Sb 9 /HfO 2 superlattice-like film is low. This paper focused the effect of the recombination of HfO 2 on the phase change behavior and crystalline properties of Ge 1 Sb 9 /HfO 2 superlattice-like phase change films. Compared with pure Ge 1 Sb 9 , the Ge 1 Sb 9 /HfO 2 superlattice-like film has higher crystallization temperature, better data retention ability and larger activation energy, indicating excellent thermal stability. With the increase of HfO 2 thickness ratio, the band gap becomes wider. Atomic force microscopy and X-ray diffraction tests illustrate that HfO 2 composite layers can inhibit the growth of grain, reduce the grain size and have a smoother surface. X-ray reflectivity tests show that Ge 1 Sb 9 /HfO 2 film has a small volume fluctuation during the crystallization process. Raman spectroscopy is used to observe the molecular vibration. Phase change memory devices based on Ge 1 Sb 9 /HfO 2 thin film are fabricated to evaluate its electrical performance. The results reveal that HfO 2 composite layers play a significant role in improving thermal stability, refining grain size and reducing power consumption on Ge 1 Sb 9 phase change film. [ABSTRACT FROM AUTHOR]

The superlattice-like Sn 15 Sb 85 /Ti phase change films were fabricated by magnetron sputtering, and the effects of Ti layer on the phase change properties and crystal structure of the Sn 15 Sb 85 films were systematically researched. With the addition of Ti layers, the crystallization temperature of the films increased, indicating their thermal stability and data retention were improved. X-ray diffraction results reflect that the presence of Ti layers restrains grain growth and refines grain size. X-ray photoelectron spectroscopy analysis reveals that the incorporation of Ti layers enhances the interatomic binding energy and improves the stability. X-ray reflectivity analysis and atomic force microscopy indicate that the Sn 15 Sb 85 /Ti films have smaller volume change and smoother surface than pure Sn 15 Sb 85 films, implying the better interfacial property and reliability. The T-type phase change memory cell based on Sn 15 Sb 85 /Ti thin film has faster operation speed (100 ns) and lower power consumption (2.6 ×10−12 J) than the conventional Ge 2 Sb 2 Te 5 material. The results show that the superlattice-like Sn 15 Sb 85 /Ti film will be a potential candidate with outstanding properties in thermostability and power consumption. • Proposing the Sn 15 Sb 85 /Ti thin film with superlattice-like structure. • Performance optimization and structural analysis of film. • PCM cells based on Sn 15 Sb 85 /Ti film was prepared and tested. [ABSTRACT FROM AUTHOR]