论文总字数：15419字

摘 要

金属多层膜具有高强度、高塑性以及良好的热稳定性等力学与物理性能，广泛应用于微电子器件与微机电系统，其力学特性直接影响电子器件的服役可靠性。然而，当多层膜的特征尺寸减小至微米、纳米尺度时，其界面结构与力学行为常表现出强烈的尺度依赖性。本文重点研究了Ag/Nb多层膜的界面结构和力学性能，利用高真空直流磁控溅射法在Si衬底上制备了单层膜厚度1~50nm的Ag/Nb多层膜，并通过X射线衍射仪和透射电子显微镜等方法表征了Ag/Nb多层膜的界面结构，利用纳米压痕技术测量了Ag/Nb多层膜的硬度。研究发现：其一，随着尺度的减小，界面结构类型按照非共格、半共格、完全共格的趋势发生演进，且界面处界面能不断减小，界面稳定性不断提高，当h=1nm时，界面处形成完全共格界面。其二，随着尺度的减小，晶体结构类型先是多晶体、再是织构、最后是超晶格，按照这样的趋势发生变化，当hlt;5nm时，多层膜则形成超晶格结构。其三，随着尺度的减小，Ag/Nb金属多层膜的硬度持续增加，未出现软化现象。当h=1nm时，金属多层膜的硬度值增加到最大值6.79GPa，分别为纯Ag膜中测量值的5.3倍和根据混合物规则计算值的2.3倍。

关键词：金属多层膜；界面结构；力学性能；尺度效应

Interface structure and mechanical properties of Ag/Nb multilayer

Abstract

Metal multilayer film has high strength, high plasticity and good thermal stability and other mechanical and physical properties. It is widely used in microelectronic devices and mEMS systems. Its mechanical properties directly affect the service reliability of electronic devices. However, when the characteristic size of the multilayer decreases to the micro - nanometer scale, the interface structure and mechanical behavior of the multilayer often show strong scale dependence. This article focuses on the interface of Ag/Nb multi-layers structure and mechanical properties, high vacuum dc magnetron sputtering method is used on the Si substrate preparation for single layer film thickness 1 ~ 50 nm Ag/Nb multilayer membrane, and through the methods such as X-ray diffraction and transmission electron microscopy (tem) characterization of the interface structure of Ag/Nb multilayer film, with nano indentation technology to measure the Ag/Nb multilayer film hardness. It is found that: First, with the decrease of the scale, the interface structure types evolve in accordance with the trend of non-coherent, semi-coherent and completely coherent; moreover, the interface at the interface can be continuously reduced and the interface stability is continuously improved; when h=1nm, a completely cograin interface is formed at the interface. Secondly, as the scale decreases, the crystal structure types first become polycrystal, then texture, and finally superlattice. At 5nm, the multilayer film forms a superlattice structure. Thirdly, with the decrease in size, the hardness of Ag/Nb metal multilayer film continues to increase without softening. When h=1nm, the hardness of the metal multilayer film increased to the maximum value of 6.79gpa, which was 5.3 times of the measured value in the pure Ag film and 2.3 times of the calculated value according to the mixture rule, respectively.

Key words: metal multilayer film; Interface structure; Mechanical properties; Scale effect

目 录

摘 要 I

Abstract II

第一章 引言 1

1.1 金属多层膜的研究现状 1

1.2 金属多层膜的结构特征和力学性能 1

1.2.1 纳米多层膜的力学性能 1

1.2.2 纳米多层膜的强化机制 2

1.2.3 纳米多层膜的界面结构 3

1.3 金属多层膜的制备方法 4

1.3.1 磁控溅射技术 4

1.3.2 磁控溅射工艺 5

1.4 实验内容和预期目标 6

第二章 实验方法 8

2.1 X射线衍射分析 8

2.2 透射电子显微镜分析 8

2.3 纳米压痕技术分析 9

第三章 试验结果分析和讨论 10

3.1 Ag/Nb多层膜的结构演化 10

3.2 金属多层膜的力学性能 14

第四章 结论与展望 16

参考文献 18

致 谢 20

第一章 引言

1.1 金属多层膜的研究现状

近年来，纳米多层膜因其高强度、热稳定性和耐辐射性等优异性能而受到广泛的研究。多层膜是由两种或两种以上不同材料相互交替形成的人工结构材料，多层膜的相邻两层形成一个调制周期，简称周期，用λ表示^[1]。当λ在纳米尺度时,这种多层结构薄膜材料被称为纳米多层膜。

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