Study of the crystallization behavior of Ag-In-Sb-Te phase change optical recording film

Abstract

Recently the demand for high-speed and high-density optical recording media using a direct overwrite scheme is very high. Among some of the potential candidates, the AgInSbTe alloy appears to be one of the promising materials that has drawn worldwide attention. It can give direct overwrite capability within a short period of time and is reported to give a well-defined shape with sharp edges, leading to intrinsically lower jitter values, thereby increasing the linear density. Hence, considerable interest has been focused on the study of the crystallization behavior of AgInSbTe alloy. Different crystalline phases are observed due to thermal annealing of AgInSbTe four-element alloy films. Results of the x-ray diffraction analysis of amorphous and crystalline (AgSbTe) x (In 1–y Sb y ) 1–x films with x = 0.2, 0.4 and y = 0.7, deposited by thermal evaporation technique are presented. The difference in crystallization behavior of the crystalline phases formed after 1 h of isothermal annealing at temperature between 200 and 400°C are studied through x-ray diffraction analysis. The experimental results are presented for a composition close to eutectic Sb 69 Te 31 in which some of the Te is replaced by Ag and In. The results indicate that the growth of the crystalline phases depends on the annealing temperature and it is also affected by the change in the composition.