Novel material for nonvolatile ovonic unified memory (OUM)–Ag_(11)In_(12)Te_(26)Sb_(51) phase change semiconductor

摘要

In this paper, Ag_(11)In_(12)Te_(26)Sb_(51) phase change semiconductor films have been prepared by d_c sputtering. The crystallization behaviour of amorphous Ag_(11)In_(12)Te_(26)Sb_(51) thin films was investigated by using differential scanning calorimetry and x-ray diffraction. It was found that the crystallization temperature is about 483K and the melting temperature is 754.8K and the activation energy for crystallization, Ea, is 2.07eV. The crystalline Ag_(11)In_(12)Te_(26)Sb_(51) films were obtained using initializer. The initialization conditions have a great effect on the sheet resistance of Ag_(11)In(12)Te_(26)Sb_(51) films. We found that the effect of the initialization condition on the sheet resistance can be ascribed to the crystallinity of Ag_(11)In_(12)Te_(26)Sb_(51) films. The sheet resistance of the amorphous (R_(amo)) film is found to be larger than 1*10~6Ω and that of the crystalline (R_(cry)) film lies in the range from about 10~3 to 10~4Ω. So we have the ratio R_(amo)/R_(cry)=10~2～10~3, which is sufficiently large for application in memory devices.