Enhanced thermal stability by heterogeneous interface and columnar grain in nanoscale Cu/Ru multilayers
Enhanced thermal stability by heterogeneous interface and columnar grain in nanoscale Cu/Ru multilayers
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纳米级 Cu/Ru 多层膜中的异质界面和柱状晶增强了热稳定性
DOI：
10.1016/j.msea.2018.10.048
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发表时间：
2019
期刊：
影响因子：
6.4
通讯作者：
Y.P.Cai
中科院分区：
文献类型：
--
作者：
C.Sun;Y.J.Ma;M.J.Cui;G.J.Wang;Z.H.Cao;X.K.Meng;Y.P.Cai
通过透射电子显微镜分析和纳米压痕实验研究了不同调制比(固定Ru层厚度为3 nm，不同铜层厚度(H)为10 nm~2 0 0 nm)的纳米级Cu/Ru金属多层膜的热稳定性。所有的Cu/Ru多层膜在400 °C温度下都保持了层状结构。随着铜层厚度的减小，铜颗粒的生长速度变慢，表现出一种反常的尺寸依赖关系，即“越小越稳定”。尤其是H= 10 nm的Cu/Ru多层膜，其平均晶粒度仅为25 nm，经400 °C退火热处理后，硬度仅下降6.5%，具有良好的稳定性。Cu/Ru多层膜热稳定性的提高源于具有较低界面能的织构柱状晶和半相异相界面。随着铜层厚度的减小，织构的柱状晶和半粘滞非均质界面的数量增加，这是提高Cu/Ru多层膜热稳定性的原因。
The thermal stability of nanoscale Cu/Ru metallic multilayers with different modulation ratio (a fixed Ru layer thickness of 3 nm and varied Cu layer thickness (h) from 10 nm to 200 nm) was investigated by transmission electron microscope (TEM) analyses and nanoindentation tests. All of the Cu/Ru multilayers retained the layered structures up to 400 °C annealing. The Cu grain growth slowed with Cu layer thickness decreasing, illustrating an unusual size dependence, that is, “smaller is more stable.” Especially the average grain size was maintained as small as 25 nm for the Cu/Ru multilayers withh= 10 nm and the hardness only decreased by 6.5% after 400 °C annealing, which exhibits an excellent stability. The enhanced thermal stability of Cu/Ru multilayers originates from the textured columnar grains and semicoherent heterogeneous interfaces, which have a low interface energy. The amount of textured columnar grains and semicoherent heterogeneous interfaces increase with the Cu layer thickness decreasing is responsible for the enhanced thermal stability of Cu/Ru multilayers.