(AlCrTiZrNb)N/Si_3N_4纳米多层膜的微观结构和力学性能研究

采用多靶磁控溅射系统,使用AlCrTiZrNb合金靶和Si靶制备了不同Si_3N_4厚度的(AlCrTiZrNb)N/Si_3N_4纳米多层膜,样品基底为单晶硅。通过X射线衍射仪(XRD)、高透射电子显微镜(HRTEM)、扫描电子显微镜(SEM)和纳米压痕仪对样品进行微观组织的表征和力学性能的测量。实验结果表明,随着Si_3N_4层厚度的增加,样品的结晶度和力学性能均先增加后减小,XRD图谱中出现面心立方相结构。在Si_3N_4层厚度为0.5 nm时,(111)衍射峰强度达到最大值。说明薄膜结晶度最强,薄膜的硬度和弹性模量也达到最高值,分别为30.6,298 GPa。通过对样品的横截面的形貌观察,发现当Si_3N_4层厚度为0.5 nm时,多层膜的多层结构生长良好。在(AlCrTiZrNb)N层的模板作用下,Si_3N_4层从非晶态转变为面心立方结构,与(AlCrTiZrNb)N层之间形成共格外延生长结构,(AlCrTiZrNb)N/Si_3N_4纳米多层膜的强化可归因于两调制层之间形成的共格界面。

Study on microstructure and mechanical properties of (AlCrTiZrNb)N/Si_3N_4 nano-multilayer films

By using AlCrTiZrNb alloy target and Si targets,the(AlCrTiZrNb)N/Si3N4 nano-multilayer films with different Si3N4 thicknesses were prepared by multi-target magnetron sputtering system on the single crystal silicon substrate.The microstructure and mechanical properties of the samples were analyzed by X-ray diffraction(XRD),high-resolution transmission electron microscopy(HRTEM),scanning electron microscopy(SEM)and nano-indentation techniques.The results showed that,as the thickness of Si3N4 layer increases,the crystallinity and mechanical properties of the sample first increase and then decrease,a cubic-structured phase appears in the XRD patterns.When the Si3N4 layer thickness is 0.5 nm,the XRD pattern presents the largest(111)peak intensity,indicating the strongest crystallinity,and the hardness and elastic modulus reach the highest values,which are 30.6 and 298 GPa,respectively.The HRTEM observations show the columnar crystal growth of the nano-multilayer films when the Si3N4 layer thickness is 0.5 nm.Under the template of(AlCrTiZrNb)N layer,the Si3N4 layer changes from amorphous to cubic phase and grow epitaxially with(AlCrTiZrNb)N layers.The strengthening of the nano-multilayer films can be attributed to the coherent interface between(AlCrTiZrNb)N and Si3N4 layers.