Improvement of Electrical Properties of the Ge₂Sb₂Te₅ Film by Doping Si for Phase-Change Random Access Memory

Si-doped Ge₂Sb₂Te₅ films have been prepared by dc magnetron co-sputtering with Ge₂Sb₂Te₅ and Si targets. The addition of Si in the Ge₂Sb₂Te₅ film results in the increase of both crystallization temperature and phase-transition temperature from face-centred-cubic (fcc) phase to hexagonal (hex) phase. The resistivity of the Ge₂Sb₂Te₅ film shows a significant increase with the Si doping. When doping 11.8 at.% of Si in the film, the resistivity after 460°C annealing increases from 1 to 11mΩ .cm and dynamic resistance increase from 64 to 99Ω compared to the undoped Ge₂Sb₂Te₅ film. This is very helpful to writing current reduction of phase-change random access memory.