Fast-growth Materials Research Articles

Effects of Ag and In addition on the optical properties and crystallization kinetics of eutectic Sb70Te30 phase-change recording film

Adding specific foreign elements into the eutectic Sb70Te30 fast-growth material is expected to be an effective way to increase its thermal stability for blue laser recording. We have studied the effects of Ag and In addition on the optical properties and crystallization kinetics of the eutectic Sb70Te30 recording film. The results showed that the addition of Ag and In increased the refractive index and decreased the extinction coefficient of amorphous Sb70Te30 film and decreased both the refractive index and extinction coefficient of crystalline Sb70Te30 film. The archival stability of the eutectic SbTe alloy could be effectively improved by adding Ag and In elements, however, the addition of Ag and In also made the initialization of the as-deposited eutectic SbTe film more difficult. During the isothermal crystallization process, the incubation time was extended, crystallization speed was reduced, and the crystallization process became more grain-growth dominated as Ag and In were added. All these effects were further enhanced by increasing the concentration of In element.

Optical Properties and Crystallization Characteristics of Ge-Doped Sb70Te30 Phase Change Recording Film

Eutectic Sb70Te30 fast-growth material is one of the promising candidates for high data transfer rate recording. However, it also shows the disadvantage of poor thermal stability. Germanium, with a high value of glass transition temperature, is expected to play the role of thermal stabilizer. It was found that the effect of Ge doping on reflectivity difference between as-deposited and annealed states is not significant. However, the addition of Ge element into Sb70Te30 can reduce the initialization or erasure power, and increase the stability of the phase change recording media at room temperature at the same time. Unfortunately, doping Ge element would also slow down the crystallization speed of eutectic Sb70Te30 recording film.