Abstract
Crystallization and thermal stability of Ge 2 Sb 2 Te 5 (GST), the benchmark working material in phase-change non-volatile memory, were modified via Si-ion implantation. Through 5 × 10 15 Si-ions/cm 2 ion-implantation, crystallization temperature increases from 165°C to 177°C. Furthermore, the activation energy of crystallization increases from 2.9 eV in the pristine film to 3.3 eV and 4.0 eV in films implanted with the doses of 5 × 10 15 and 5 × 10 16 Si-ions/cm 2 , respectively. Temperatures corresponding to a 10-year failure-time increase from 83°C in the pristine film to 96°C and 107°C in films implanted with 5 × 10 15 and 5 × 10 16 Si-ions/cm 2 , respectively. Thermal stability of Si-ion implanted GST thus improves significantly. It was also found that grain growth is inhibited with higher implantation doses. In the case of the 5 × 10 16 ion/cm 2 dose, the second-phase transition from face-centered cubic to hexagonal closed-packed structure of the GST is completely inhibited. However, crystallization time increases slightly due to Si-ion implantation. © 2012 Elsevier B.V. All rights reserved.