Metallic Nanocomposite Films for NEMS Applications
Most structural components in nanoelectromechanical systems (NEMS) are synthesized from single crystal or polycrystalline silicon, carbide, nitride, or diamond films, with silicon being by far the most widely used. However, silicon has low fracture strength and poor wear characteristics and is poorly suited for electrically conductive and magnetic sensing applications. Metallic films can provide better ductility and higher electrical conductivity but generally suffer from low strength and low stiffness. Pure aluminum, in particular, also has large surface roughness, precluding its usage in most NEMS applications.
To address these problems, researchers at the University of Alberta and Lawrence Berkeley National Laboratory have jointly fabricated nanocomposite films with significantly improved strength and surface smoothness. These aluminum-molybdenum (Al-Mo) and nickel-molybdenum (Ni-Mo) films are electrically conductive, and in the case of Ni-Mo, also magnetic, at room temperature. The low roughness also enables these films to be made as thin as 5 nm. Because of these films’ unique microstructure, the NEMS cantilevers fabricated from these films are stress-free and not subject to warping.
- Both Al-Mo and Ni-Mo films are reasonably conductive at room temperature, Ni-Mo also magnetic
- Stress-free and smooth—films can be fabricated to as thin as 5 nm
- Excellent mechanical properties (hardness, strength, stiffness, etc.)
- Simple method that uses easily processable materials
The cantilevers are applicable in atomic force microscopy, including variations such as capacitance, tunnelling, resistive, and magnetic. The cantilevers are useful for probing organic and inorganic materials in research, for gas-sensing in industries such as chemical and petrochemical, and for usage as quantum tunnelling diodes, transistor structures, probe pods, and crack stops in microelectronics. The nanocomposite films may also have applications in the coatings and thin films industry.
Although care has been taken in the preparation of this material to be as accurate as possible, the contents of this document are provided for information purposes only, and neither the University of Alberta nor the inventors offer any warranty, written or implied, as to the accuracy of the said contents.