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MM8.1.1

Synthesis and Characterization of Amorphous Metallic Alloy Thin Films for MEMS Applications Senthil N Sambandam1, 2, Shekhar Bhansali1, Venkat R. Bhethanabotla2 1 Department of Electrical Engineering 2 Department of Chemical Engineering University of South Florida, 4202 E. Fowler Ave., ENB 118, Tampa, FL 33620

ABSTRACT Microstructures of multi-component amorphous metallic glass alloys are becoming increasingly important due to their excellent mechanical properties and low coefficient of friction. In this work, thin films of Zr-Ti-Cu-Ni-Be have been deposited by DC magnetron sputtering in view of exploring their potential technological applications in fields such as Micro Electro Mechanical Systems (MEMS). Their structure, composition, surface morphology, mechanical properties viz., hardness and Young’s modulus were analyzed using X-Ray Diffraction (XRD), Atomic Force Microscopy (AFM), Scanning Electron Microscopy (SEM) and Nanoindentation. Influence of the deposition parameters of sputtering pressure and power upon the composition and surface morphology of these films has been evidenced by SEM, and AFM analysis, showing that such a process yields very smooth films with target composition at low sputtering pressures. These studies are useful in understanding the multicomponent sputtering process. INTRODUCTION Micro Electro Mechanical Systems have attracted intense research activity in the recent past due to their technological potential and wide applications. MEMS devices with superior performance with increased functioning, reliability, robustness and long life are required for any application. However, MEMS devices often fail due to wear of micromechanical components. Several methods [1-4] have been proposed to overcome wear of MEMS components. We propose to use high wear resistant and high strength amorphous metallic alloy thin films for fabrication MEMS structures. Thin films of amorphous metallic alloys exhibit high yield strength, large elastic limit, low Young’s modulus in addition to high wear resistance and corrosion resistance. Of the amorphous metallic alloys, Zr-Ti-Cu-Ni-Be alloys are attractive due to their low Young’s modulus and higher wear resistance in comparison with Fe-based, Al-based, and Pd-based amorphous metallic glasses [5]. They also possess mechanical isotropy, structural homogeneity and absence of crystalline defects such as lattice defects, grain boundary, segregation etc. making them suitable for MEMS fabrication. We have developed processes to fabricate amorphous thin films from a Zr-Ti-Cu-Ni-Be alloy by sputtering. Sputter deposition of multicomponent material such as Zr-Ti-Cu-Ni-Be alloys is complex due to their inhomogeneous distribution in sputter plasma density, angular ejection of sputtered atoms, differential sputtering yield of individual elements, differential transport of sputtered atoms and selective condensation at the substrate, all of which affect

MM8.1.2

composition and hence the properties of the films. Hence, we have carried out detailed studies on the effec