Preparation and characterization of microtubes of amorphous metallic thin film systems

与结晶金属膜相比，非晶金属膜具有更低的表面粗糙度、更好的耐腐蚀性和更高的弹性极限。因此，它们可以作为薄膜技术中的新材料，即用于高应力微机电系统（MEMS）或用于传感器和执行器应用。自组装卷起微管技术是一种很有前途的新型制造方法。对于非晶或非晶金属薄膜，迄今为止还没有详细研究过卷起所必需的薄膜本征应力梯度。在本项目中，非晶金属薄膜和那些能够与非晶层反应的晶体薄膜系统将通过磁控溅射生产，并在结构和应力状态方面进行表征。从这些层中，经过非晶化反应，可以制造出自辅助卷起的微管。在这一步中，将使用通过光刻技术适当构造的牺牲层。Ni-Zr作为一种众所周知的二元金属体系，能够在固态反应中非晶化，因此首先被选择。随后，研究将扩展到Cu-Ti组合。后者也可以非晶沉积，而且与Ni-Zr相比，它表现出更高的导电性和更好的Si附着力。为了更详细地了解所涉及的过程，应广泛研究卷起和非晶化微管的界面性质和结构，特别是考虑与不同制造参数和化学计量的相关性。管的进一步机械特性将通过压缩和弯曲试验以及使用纳米压痕装置来确定。

Amorphous metallic films exhibit lower surface roughness, better corrosion resistance and a higher elastic limit compared to crystalline metal films. Thus they can find application as new materials in thin film technology, namely for highly stressed micro-electro-mechanical systems (MEMS) or for sensor and actuator applications. A promising novel fabrication approach is the technique of self-assembling rolled-up micro tubes. The gradient of intrinsic film stress being necessary for rolling up has not been studied so far in detail for amorphous or amorphised metal films.In the present project, amorphous metal films and those crystalline film systems being able to react to amorphous layers shall be produced by magnetron sputtering and shall be characterized in regard to structure and stress state. From these layers, self-assisted rolled-up micro tubes shall be fabricated followed by an amorphisation reaction. Sacrificial layers structured appropriately by lithography are to be used in this step. Ni-Zr as a well-known binary metal system being able to amorphise in a solid state reaction is chosen in the first place. Subsequently, investigations are to be expanded to the Cu-Ti combination. The latter can also be deposited amorphously, furthermore it shows an increased electrical conductivity compared to Ni-Zr and better adhesion on Si.To get more detailed insights in the processes involved, the interface properties and the structure of the micro tubes rolled-up and amorphised shall be studied extensively, considering especially correlations to varied parameters of fabrication and stoichiometry. Further mechanical characteristics of the tubes are to be determined by compression and bending tests and by using a nanoindentation device.