Preparation of Te-based compound target for amorphous semiconductor thin film
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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.
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