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The physical and electrical properties of SixSb2Te system materials with various Si contents have been systemically studied with the aim of finding the most suitable composition for the phase change random access memory (PCRAM) applications. SixSb2Te shows better thermal stability than Ge2Sb2Te5 due to no Te separation under high annealing temperatures. The increase of Si content can enhance the data retention ability of SixSb2Te materials. When the value of x is larger than 0.44, the 10-year data retention temperature for SixSb2Te will exceed 110 °C, which meets the long-term data retention requirement. Furthermore, Si-rich SixSb2Te materials exhibit the improvement on thickness change after annealing compared with Ge2Sb2Te5. In addition, the PCRAM devices based on SixSb2Te (x = 0.31, 0.44) were fabricated and the electrical operations were carried out. Both of them show the outstanding performances with long-term operations. [ABSTRACT FROM AUTHOR]

The microstructure and thermal properties of Si-implanted Sb2Te3 were investigated. Crystalline Si-implanted Sb2Te3 film with relatively uniform composition depth profile was fabricated, which consists of Si4-x (0 < x < 1) ions and crystalline Sb2Te3. No separated Te phase was found. The crystallization activation energies of crystallization increase with Si dose from 5 × 1015 to 2.16 × 1016 Si-ions/cm2. The crystallization temperatures of the films are 149, 168, and 174 °C with 5 × 1015, 1 × 1016, and 2.16 × 1016 Si-ions/cm2 ion implantation, respectively. Furthermore, the Sb2Te3 film implanted with the dose of 1 × 1016 Si-ions/cm2 can maintain the data for 10 yr at 85 °C, which is comparable to Ge2Sb2Te5. The results indicate that the Si-implanted Sb2Te3 is a promising candidate for phase change memory application. [ABSTRACT FROM AUTHOR]

Si-Sb4Te phase change thin films with different silicon contents have been investigated by in situ heating technique in transmission electron microscopy (TEM). The studies show that Si-doping can significantly improve the thermal stability of Si-Sb4Te thin films, refine their grain size, and change the nucleation characters with the increase of silicon content. By in situ annealing in TEM, the crystalline phase of Si-Sb4Te thin films can be indexed as hexagonal Sb structure, and Si is still holding amorphous state which is considered as the reason for the change, by destroying the long-range order lattice of crystal grains. [ABSTRACT FROM AUTHOR]

Compared with Ge2Sb2Te5, Ge0.61Sb2Te has higher crystallization temperature (∼200.5 °C), larger crystallization activation energy (∼3.28 eV), and better data retention (∼120.8 °C for 10 yr). The switching between amorphous and crystalline state could be triggered by the electric pulse of as short as 10 ns. With the resistance ratio of two orders of magnitude, the endurance test was up to 106 cycles. Ge0.61Sb2Te material is a promising candidate for the trade-off between programming speed and data retention. [ABSTRACT FROM AUTHOR]