Si-Sb-Te materials including Te-rich Si_2Sb_2Te _6 and SixSb_2Te_3 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_xSb_2Te_3 shows better thermal stability than Ge_2Sb_2Te_5 or Si_2Sb _2Te_6 in that Si_xSb_2Te_3 does not have serious Te separation under high annealing temperature. As Si content increases, the data retention ability of Si_xSb _2Te_3 improves. The 10 years retention temperature for Si_3Sb_2Te_3 film is ～ 393K, which meets the long-term data storage requirements of automotive electronics. In addition, Si richer Si_xSb_2Te_3 films also show improvement on thickness change upon annealing and adhesion on SiO_2 substrate compared to those of Ge_2Sb_2Te_5 or Si _2Sb_2Te_6 films. However, the electrical performance of PCRAM cells based on Si_xSb_2Te_3 films with x > 3.5 becomes worse in terms of stable and long-term operations. Si_xSb_2Te_3 materials with 3 < x < 3.5 are proved to be suitable for PCRAM use to ensure good overall performance.
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