纳米多层高熵难熔合金的扩散阻挡性能

Diffusion barrier performance of nanolayered high entropy alloy films

本工作研究了纳米高熵合金单层和多层阻挡层的扩散阻挡性能及其失效行为。结果表明:非晶态NbMoTaW单层阻挡层的失效温度达到600℃,高于W和TiVCr阻挡层的500℃。W/NbMoTaW多层阻挡层为纳米晶结构,柱状晶界面为原子扩散提供了扩散通道,削弱了层界面的扩散阻挡作用,导致W/NbMoTaW多层阻挡层的失效温度与NbMoTaW阻挡层相比并没有提升,仍为600℃。然而,高熵合金NbMoTaW/TiVCr多层阻挡层的失效温度显著提高到800℃,表现出优异的扩散阻挡特性。无晶界扩散通道的非晶态结构、强晶格畸变和迟滞扩散效应的高熵合金层降低了原子扩散速率,且原子优先沿着非共格高熵界面发生扩散,原子的扩散距离增加了,这些是NbMoTaW/TiVCr多层阻挡层失效温度显著提高的主要原因。

In this work,the diffusion barrier performance and failure behavior of single-layered and multilayered high entropy alloy films were investigated.The results show that the failure temperature of amorphous NbMoTaW single barrier layer is 600℃,which is higher than 500℃of W and TiVCr single barrier layers.The W/NbMoTaW multiple barrier layer is nanocrystalline structure,and the columnar grain boundaries provide diffusion paths for atomic diffusion and weaken the diffusion barrier effect of the layer interface.As a result,the failure temperature of the W/NbMoTaW multiple barrier layer is still 600℃,which is the same as that of the NbMoTaW barrier layer.However,the failure temperature of NbMoTaW/TiVCr multiple barrier layer significantly increases to 800℃,which shows an excellent diffusion barrier performance.The amorphous structure without diffusion paths,the high entropy alloy layer with severe lattice distortion and sluggish diffusion effect reduces the atomic diffusion rate,and the atoms preferentially diffuse along the incoherent high entropy interface and increase the diffusion distance,which are the main reasons for the significant increase of the failure temperature of NbMoTaW/TiVCr multiple barrier layer.