Preparation method and application of aluminum-scandium alloy sputtering target

Abstract

The invention provides a preparation method and application of an aluminum-scandium alloy sputtering target. The content of Sc is 8at%-53at%, the density is greater than 99%, the sum of the mass percentages of Al and Sc elements is greater than 99.9%, the oxygen content is less than 50ppm, and the aluminum-scandium alloy sputtering target is suitable for sputtering for forming a piezoelectric material film. The process is adjusted according to different Sc contents, the operation is simple, the oxygen content is low, the density is high, the components are uniform, and the segregation phenomenon is avoided.

Description

technical field [0001] The invention relates to a preparation method and application of an aluminum scandium alloy sputtering target. Background technique [0002] With the rapid development of communication technology, the application frequency of surface acoustic wave (SAW) devices is increasing day by day. Using the combination of piezoelectric film and high-sonic substrate material, higher frequency SAW devices can be prepared under the same process conditions. AlN thin films not only have the characteristics of high sound velocity, wide band gap, high hardness, high temperature stability, high resistivity and low insertion loss, but also have the characteristics of being compatible with complementary metal oxide semiconductor (CMOS) process, so in SAW devices are widely used. [0003] Compared with ZnO and PZT films, the piezoelectric constant of AlN (d 33 ) and low electromechanical coupling coefficient, which limits the application of AlN thin films in SAW devices....

AI Technical Summary

Problems solved by technology

[0004] The scandium content and microstructure of the aluminum-scandium alloy target are important factors affecting the performance of the ScAlN piezoelectric thin film; since the melting point of metal scandium is 1541°C, which is quite different from the melting point of aluminum at 660°C, the commonly used medium-frequency induction melting casting method prepares aluminum scandium Alloy ingots have severe segregation and low Sc content (less than 5%)

Chinese patent specifications CN201711308051.0, CN201510185516.2, and CN201610677045.1 disclose methods for preparing Al-Sc alloy targets using powder metallurgy, which can prepare targets with high Sc content, but the powder metallurgy method has high oxygen content and high density. The low problem affects the use effect of the target

Chinese patent specification CN201811144477.1 discloses a method for preparing aluminum-scandium alloy targets prepared by cold crucible suspension smelting combined with frequency conversion electromagnetic stirring. Since the bottom of the crucible is an integral structure, this method does not form a Lorentz force that repels the melt , the melt loses a lot of heat in contact with the crucible at the bottom, forming a thicker solidified shell, and the Al with a larger specific gravity during the melting process 3 Alloy particles such as Sc are easy to condense at the bottom, resulting in a low composition of the cast alloy ingot. At the same time, there are more raw materials left in the crucible during casting, resulting in greater losses.

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