Oxygen-doped Sb4Te phase change films for high-temperature data retention and low-power application

The amorphous-to-crystalline transitions of oxygen-doped Sb4Te (STO) films are investigated by in situ film resistance measurements. The crystalline temperature and resistance of the oxygen-doped films increase. The analysis of X-ray diffractomer (XRD) and X-ray photoelectron spectroscopy (XPS) indicate that the films with doping of a small amount of oxygen atoms can refine the grain size and form oxide, improving the resistance and thermal stability of phase change films. Excessive oxygen in Sb4Te will make Te separate, resulting in deteriorating the stability. As a result, STO2 film has the relatively high activation energy for crystallization. The 10-year lifetime is raised from 29 °C of undoped Sb4Te film to 102 °C of STO3 film. Phase transition from amorphous state to crystalline state is observed at relatively lower power, compared with a device using Ge2Sb2Te5 film.

► O-doped Sb4Te phase-change films were reported.
► The amorphous-to-crystalline transitions of O-doped Sb4Te films were studied.
► By doping oxygen, the stability of Sb4Te films is improved greatly.
► The resistance of the Sb4Te films increases by doping oxygen.