Structure stability of high aspect ratio Ti/Au two-layer cantilevers for applications in MEMS accelerometers

• The structure stability of the Ti/Au two-layer micro-cantilevers was studied.
• The cantilevers had lengths from 100 to 1000 μm and thickness from 3 to 12 μm.
• The stability was low when the cantilever is long with a smaller thickness of 3μm.
• The stability was high for all of the cantilevers with thickness larger than 10 μm.
• The results confirmed the Ti/Au two-layer structure can improve the stability.

This paper reports the structure stability of Ti/Au two-layer micro-cantilevers with various aspect ratios based on the results obtained from a 3D optical microscope and FEM simulation. The cantilevers were fabricated by MEMS fabrication process. The movable structure stability was investigated by observing the shape of the Ti/Au two-layer micro-cantilevers with the Ti layer thickness of 0.1 μm, and the Au layer thicknesses of 3 μm, 10 μm and 12 μm. The length was varied from 100 to 1000 μm. The results of the tip deflection observed from the 3D optical microscope were similar to those of the FEM simulation. The experimental results of the micro-cantilevers with the Au thickness of 12 μm indicated the highest structure stability. In conclusion, these results revealed that the Ti/Au two-layer structure can enhance the stability and reliability of the movable structure.

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