Elevated temperature co-sputtering of immiscible elements results in a variety of self-organized morphologies due to phase separation. Cu–Ta is used as a model system to understand the evolution of phase-separated microstructural morphologies by co-sputtering thin films with nominal 50–50 at.% composition at four temperatures: 25, 400, 600, and 800 °C. Scanning/transmission electron microscopy of the film cross sections showed the microstructure morphology varied from nanocrystalline Cu–Ta at 25 °C to a wavy ribbon-like structure at 400 °C, to Cu-rich agglomerates surrounded by Ta-rich veins at 600 and 800 °C. In the agglomerate-vein morphology, microstructural features were present on two length scales, from a few nanometers to a few tens of nanometers, thus making the structures hierarchical. On the nanoscale, the Cu-rich agglomerates contained Ta precipitates, whereas the Ta-rich veins had embedded Cu nanocrystals. The various microstructures can be attributed to the highly disparate constituent element interdiffusion at the deposition temperatures with the Cu having orders of magnitude higher mobility than Ta at the deposition temperatures. This study of processing–microstructure relationship will be useful in guiding the design of hierarchical multiphase microstructures in binary or multicomponent thin films with tailored mechanical properties.

由于相分离，不混溶元素的高温共溅射会导致多种自组织形态。Cu-Ta作为模型系统通过在25、400、600和800°C的四个温度下共同溅射标称成分为50–50 at。％的薄膜来理解相分离的微观结构形态的演变。薄膜截面的扫描/透射电子显微镜显示微观结构形态从25°C的纳米晶体Cu-Ta到400°C的波浪状带状结构，再到600和600℃被富Ta脉包围的富Cu团聚体800℃。在附聚物-静脉形态中，微观结构特征存在于从几纳米到几十纳米的两个长度尺度上，从而使结构分层。在纳米尺度上 富含铜的团聚体中含有Ta沉淀物，而富含Ta的脉中则嵌入了Cu纳米晶体。各种微观结构可归因于在沉积温度下高度不同的组成元素相互扩散，其中Cu在沉积温度下的迁移率比Ta高。对加工-微观结构关系的研究将有助于指导具有定制机械性能的二元或多组分薄膜中的分层多相微观结构的设计。