Elastic and plastic energy analysis for multilayered thin films by nanoindentation

一、基片/Al/TiN双层薄膜本研究中所研究的基片/Al/TiN双层薄膜是在超高真空多阴极溅射装置上用反应溅射法沉积的。靶为75 mm Al（99.99%）和Ti（99.98%）。使用的基板是铝硅酸盐玻璃。Al层的厚度从0到500 nm变化。为了避免TiN/Al层界面的直接破坏，在基底/Al/TiN双层膜的顶层镀上了500 nm的TiN，随着Al层厚度的增加，膜的硬度降低。通过纳米压痕评估的耗散能量随着Al层厚度的增加而增加。对于大的触针负载，耗散能量的增加更显著。弹性能几乎与Al厚度无关。从塑性能和弹性能与铝层厚度的关系可以看出，塑性变形主要发生在软铝层中， ...更多信息 研究了基体/（Al/TiN）_n/TiN多层膜，讨论了Al和TiN层在纳米压痕下的塑性和弹性行为中的作用。研究的层数为2、20和40。还沉积了厚度为500 nm的TiN顶层。所用的沉积和压痕设备与上述相同。对于Al厚度为100 nm且具有20或40层结构的膜，观察到硬度增强。对于Al厚度的进一步增加，硬度单调降低所有层结构。用纳米压痕法测量了基底/（Al/TiN）_n/TiN多层膜的能量耗散，结果表明，随着Al厚度的增加，多层膜的能量耗散逐渐增加。另一方面，弹性能几乎与Al厚度无关。随着Al厚度的增加，耗散能量与加载能量的比率几乎单调增加。然而，具有100 nm Al厚度和40层结构的膜的比率与单片TiN单层膜的比率相比指示较小的值。这意味着该膜比整体TiN更有弹性。厚度为5 nm的薄Al层不充当发生塑性变形的层。在这个薄层中，在薄膜中的界面处的应力和应变被认为是导致多层薄膜的异常行为的原因。III.衬底/（PTFE/TiN）和（PTFE/Ti）多层薄膜衬底/（PTFE/TiN）_n和（PTFE/TiN）_n多层薄膜已经被检查，以讨论软PTFE层在纳米压痕下的塑性和弹性行为中的作用。膜层层数为2、10、20、40和60层，膜层硬度随层数的增加而增加。弹性能也随层数的增加而增加。PTFE/TiN层系统的弹性能随膜层厚度的增加而增加，比PTFE/Ti层系统的弹性能随膜层厚度的增加而增加的更为显著。这被认为与两层材料之间的表面自由能差异有关。纳米压痕能量分析表明，PTFE薄层作为一种反常层，增加了薄膜的弹性。少

I.Substrate/Al/TiN bilayered thin flimsSubstrate/Al/TiN bilayered films examined in this study have been deposited by reactive sputtering using the ultra high vacuum multi cathode-type sputtering apparatus. Targets were 75mm Al (99.99%) and Ti (99.98%). Substrate used was aluminosilicate glass. The thickness of Al layer was varied from 0 to 500nm. The toplayer of TiN with a thickness of 500 nm was coated to avoid a direct destruction of interface (s) of TiN/Al layers.The hardness obtained for Substrate/Al/TiN bilayered films decreases with increasing Al layer thickness. The dissipated energy evaluated by nanoindentation increases with increasing Al layer thickness. The increase in the dissipated energy is more significant for a large stylus load. The elastic energy is nearly independent of Al thickness. From the dependencies of plastic and elastic energies on Al thickness, it is concluded that the plastic deformation occurs mainly in the soft Al layer and that the elastic deformation o … More ccurs mainly in the TiN layer.II.Substrate/(Al/TiN) multilayered thin filmsSubstrate/(Al/TiN)_n/TiN multilayered films have been examined in order to discuss role of Al and TiN layer in plastic and elastic behavior under the nanoindentation. The number of layers studied was 2, 20 and 40. The toplayer of TiN with a thickness of 500 nm was also deposited. The deposition and indentation apparatus used are the same as descried above.For films with an Al thickness of 100 nm and with 20 or 40-layered structure, the hardness enhancement is observed. For a further increase in Al thickness, the hardness decreases monotonically for all layer structure. The dissipated energy evaluated by nanoindentation for substrate/(Al/TiN)_n/TiN multilayered films increases with Al thickness. on the other hand, the elastic energy is nearly independent of Al thickness. The ratio or dissipated to loaded energy increases nearly monotonically with increasing Al thickness. However the ratio of the film with 100nm Al thickness and 40 layered structure indicates a smaller value compared to that of the monolithic TiN single layer film. This implies that this film is more elastic than the monolithic TiN.The thin Al layer of 5 nm thickness does not act as the layer in which plastic deformation occurs. In this thin layer, the stress and strain at the interface in a thin film are thought to cause abnormal behaviors of the multilayered thin films.III.Substrate/ (PTFE/TiN) and (PTFE/Ti) multilayered thin filmsSubstrate/(PTFE/TiN)_n and (PTFE/TiN)_n multilayered films have been examined in order to discuss role of soft PTFE layer in plastic and elastic behavior under the nanoindentation. The number of layers studied was 2, 10, 20, 40, and 60.The hardness of the film increses with increasing the number of layeres. The elestic energy is alos increasing with increasing the number of layer. The increase in the elestic energy with increasing the film layer is more remarkable for PTFE/TiN layer system than for PTFE/Ti layer system. This is thought to relate to the difference in the surface free energy between the two layer materilas. The energy analysis by nanoinddentation clarify that the thin PTFE layer act as an abnormal layer that increases the elesticity of the film. Less