力电耦合下铜基纳米多层膜界面效应和传导性质研究

The single-/multi-layered films are widely used as essential components of high performance microelectronics, microelectromechanical systems and interconnect structures owing to their outstanding mechanical/electric properties. The nanostructured Cu-based multilayers work in micro-nano scale, heterogeneous layer-to-layer interfaces and under coupling of electric field and stress field. The working life and conduction properties of Cu-based multilayers are widely concerned and regarded as a basic sicientific issue. On the basis of the preliminary work,the nanostructured crystalline Cu/crystalline Zr and crystalline Cu/amorphous Cu-Zr multilayers with different modulation periods have been prepared on Si substrate by magnetron sputtering. By regulating component scales, modulation structure, crystal structure and microscopic features of the interface structure, comprehensive utilization of focused ion beam (FIB), in situ mechanical testing methods combined with transmission electron microscopy (PI95) and computer simulations, the cycles of experiment - simulation - experimental are repeated. By studying the correlation between sample size and interface structure, conduction properties,the size-dependent interface model of copper-based multilayers has been established under coupling of electro-mechanical field. Through comparing with the conduction properties of the a single component film with an equal thickness under single filed work condition, the mechanism of structure failure and conductivity attenuation is clarified and the key factor can be found out. And the physical nature of the conduction properties is explored from atomic and electronic scale. The research results reveal the interface structure evolution and conduction behavior of copper-based nano-multilayers, which may provide important guidance and reference for nano-electromechanical coupling under conditions of multilayer films in MEMS device design and applications.

针对铜基纳米多层膜在柔性显示器，柔性太阳能电池及其他微电子器件中微尺度、层状异质、界面约束和多场耦合的服役条件特征，申请者基于前期工作，在Si基板上通过磁控溅射方法制备不同组元，不同调制周期的晶体/晶体(Cu/Zr)和晶体/非晶(Cu/Cu-Zr)纳米多层膜。通过调控组元尺度、调制结构、晶体结构以及界面结构等微观特征，采用聚焦离子束(FIB)、透射电镜联用力学设备(PI95)原位力学测试与计算机模拟相结合的方法，进行实验-模拟循环优化。研究其试样尺寸与界面能、传导性质的相关性，建立铜基纳米多层膜力电耦合下异质界面的尺寸依赖的模型。并与等厚度的单质膜、单场作用下服役性能和传导性质进行对比，阐明力场和电场耦合对铜基纳米多层膜传导性质的影响规律，从原子和电子量级对传导性质的物理本质进行探讨，揭示铜基纳米多层膜界面结构演变及传导行为，为力电耦合条件下纳米多层膜的设计、应用等提供重要的指导和参考。

针对铜基纳米多层膜在柔性显示器，柔性太阳能电池及其他微电子器件中微尺度、层状异质、界面约束和多场耦合的服役条件特征，我们在单晶Si基板上磁控溅射法沉积Cu、Zr单质膜以及不同组元，不同调制周期的晶体/晶体(Cu/Zr)与晶体/非晶(Cu/CuxZr100-x）（原子百分比）多层膜。用FIB技术直接加工出不同厚度，自由的微小尺寸多层膜试样。磁控溅射制备的晶体/非晶Cu/CuxZr100-x多层膜晶体/非晶界面清晰，且非晶层完全非晶化。通过调控组元尺度、调制结构、晶体结构以及界面结构等微观特征，采用聚焦离子束(FIB)、透射电镜联用力学设备(PI95)原位力学测试与计算机模拟相结合的方法，进行实验-模拟循环优化。在研究中，我们发现在力电耦合作用下Cu/Cu50Zr50多层膜，表现出最佳的传导性质和柔韧性。探寻了力电耦合下, 铜基纳米多层膜传导性质及其主控因素，并阐明力场和电场对铜基纳米多层膜传导性质和界面能的影响规律，为力电耦合条件下纳米多层膜在柔性显示器，柔性太阳能电池及其他微电子器件中的设计、应用等提供重要的指导和参考。此外，我们还发现相对于Cu/Cu50Zr50多层膜，Ag/Ag30Ni70纳米多层膜具有更加优异的柔韧性，只是传导率略低于Cu/Cu50Zr50铜锆多层膜。因此，Ag基纳米多层膜也有望用于微电子器件中。并研究了力电耦合对柔性衬底的影响，为多层膜与衬底结合应用于柔性材料中进行了理论探索。