非晶半导体薄膜用Te系化合物靶材制备
Preparation of Te-based compound target for amorphous semiconductor thin film
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摘要: 采用真空熔炼法, 经急冷和缓冷两种不同冷却条件制备了Te系化合物TeAsGeSi合金粉体.通过X射线衍射分析, 急冷工艺制备粉体呈非晶态, 缓冷工艺制备的粉体呈晶态, 结晶主相为R-3m空间群的As2GeTe4; 差热-热重分析显示, 升温至350℃时缓冷粉体As2GeTe4成分熔融, 400℃时两种粉体均开始快速失重, 为避免制备过程中发生材料熔融及挥发损失, 确定烧结温度不超过340℃.采用真空热压法制备TeAsGeSi合金靶材, 将两种粉体分别升温至340℃, 加压20 MPa, 保温2 h制备出两种靶材, 其中缓冷粉体制备的靶材致密度高, 为5. 46 g·cm-3, 达混合理论密度的99. 5%, 形貌表征显示此靶材表面平整, 孔洞少, 元素分布均匀.Abstract: When a certain threshold switching voltage is applied to a semiconductor of Te-based compound in a high-impedance amorphous state, the semiconductor transits into a low-resistance state, and the resistance difference is more than five orders of magnitude. Therefore, TeAsGeSi material can be prepared as a threshold switch and used in the form of a thin film in a phase-change memory and other elements to improve the performance of such elements. There are few studies on the preparation of such targets, and the key technologies have been monopolized. In this study, the powder difference was taken as the basis to study the target material preparation process of this material in order to prepare a target with high density and uniform composition. Two kinds of TeAsGeSi alloy powders were prepared by vacuum melting under different cooling conditions: quenching and slow cooling. The X-ray diffraction (XRD) analysis shows that the powder prepared by rapid cooling is amorphous, while the powder prepared by slow cooling process is crystalline, and the main crystal phase is As 2GeTe4. The differential scanning calorimetry and thermogravimetry (DSC-TG) curves of the two powders shows that the powders begin to lose weight quickly at 400 ℃, and the slowly cooled powder melts at 350 ℃. As a result, the sintering temperature must not exceed 340 ℃. The TeAsGeSi alloy target was prepared by vacuum hot pressing. The two powders were incubated at 340 ℃ for 2 h and 20 MPa to prepare two targets. The target material prepared by the slowly cooled powder has a high density of 5. 46 g·cm-3, reaching 99. 5% of the theoretical density. The morphological characterization shows that the target has a smooth surface with few holes and uniform distribution of elements, and this target can produce high-performance thin films.