| Summary: | 碩士 === 國立成功大學 === 材料科學及工程學系碩博士班 === 92 === This study aims to prepare Ag-In-Sb-Te amorphous thin films with various Ag contents by sputtering and investigates the effect of Ag content on the phase stability and optical properties.
In order to evaluate the phase stability of amorphous films, differential Scanning Calorimeter（DSC） is applied to examine the exothermic behavior of crystallization under different heating rates. Also, the Kissinger method is used to calculate the activation energy for crystallization. The results show that an increase in Ag content causes a higher activation energy, and thus makes the crystallization process more difficult. This implies that increasing Ag content can improve the phase stability of Ag-In-Sb-Te amorphous films.
The results of phase analysis by X-ray diffraction show that after the crystallizing heat treatment held at different temperatures (160 oC、180 oC、200oC、250 oC、300 oC), the microstructure of the Ag-In-Sb-Te films is a mixture of Sb and small amount of AgInTe2. Notably, AgInTe2 can not be detected in the 6 Ag and 13Ag specimens suffering the heat treatment at 200oC.
Optical properties of the films with amorphous and crystallized states are also investigated. The results indicate the reflectivity of the amorphous of 6Ag and 13Ag films are similar but 8Ag specimen is lower others, however, those of the crystallized films decreases in turn from 6Ag, 8Ag and 13 Ag. Therefore, reflectivity contrast of the 8Ag sample is greater than that of the 6Ag specimen, which is in turn greater than that of the 13Ag specimen.
From the aforementioned properties, this study proposes that the Ag-In-Sb-Te thin film with the Ag content of 8 at%, which possesses appropriate phase stability and superior optical performance, is recommended for application as the recording material for CD-RW disc.
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