Si-Sb-Te materials for phase change memory applications

Si-Sb-Te materials including Te-rich Si₂Sb₂Te ₆ and Si_xSb₂Te₃ with different Si contents have been systemically studied with the aim of finding the most suitable Si-Sb-Te composition for phase change random access memory (PCRAM) use. Si_xSb₂Te₃ shows better thermal stability than Ge₂Sb₂Te₅ or Si₂Sb ₂Te₆ in that Si_xSb₂Te₃ does not have serious Te separation under high annealing temperature. As Si content increases, the data retention ability of Si_xSb ₂Te₃ improves. The 10 years retention temperature for Si₃Sb₂Te₃ film is ∼ 393K, which meets the long-term data storage requirements of automotive electronics. In addition, Si richer Si_xSb₂Te₃ films also show improvement on thickness change upon annealing and adhesion on SiO₂ substrate compared to those of Ge₂Sb₂Te₅ or Si ₂Sb₂Te₆ films. However, the electrical performance of PCRAM cells based on Si_xSb₂Te₃ films with x > 3.5 becomes worse in terms of stable and long-term operations. Si_xSb₂Te₃ materials with 3 < x < 3.5 are proved to be suitable for PCRAM use to ensure good overall performance.