Search

The development and characterisation of a piezoelectric actuated high-frequency MEMS scanning mirror with on-chip frequency tuning capability is reported. The resonant scanner operates at frequencies in excess of 140 kHz, generating scan angles of 10° and 6° for two orthogonal movement modes with 40 V actuation. On-chip frequency tuning is achieved through electrothermal actuators fabricated adjacent to the mirror main suspension. The electrothermal actuators produce a global and local temperature increase which changes the suspension stiffness and therefore the resonant frequency. A resonance frequency tuning range of up to 5.5 kHz is achieved, with tuning dominant on only one of the two orthogonal scan movement modes. This opens the possibility for precise tuning of a 2D Lissajous scan pattern using a single resonant MEMS scanner with dual orthogonal resonant modes producing full frame update rates up to 20 kHz while retaining the full angular range of both resonant movement modes. [ABSTRACT FROM AUTHOR]

This paper reports a simple technique to measure the anisotropy of the Young's modulus of MEMS materials using coupled cantilevers. The technique is demonstrated in single-crystal silicon with an array of cantilevers fabricated in (100) silicon following a “wagon wheel” configuration. The long axis of the cantilevers had different angular orientations to the [110] direction. The parasitic coupling due to undercut below the cantilevers, which is often observed during etching of MEMS, led to a collective behavior in the frequency response of the cantilevers. This collective behavior was used in association with an inverse eigenvalue analysis to obtain the Young's moduli for the different orientations. Further analysis of the technique relating to accuracy and precision required in the resonance frequency measurement has also been presented.\hfill [2012-0084] [ABSTRACT FROM AUTHOR]

Abstract: As microelectromechanical systems (MEMS) become more complex and is produced in even greater numbers it becomes increasingly important to have a full understanding of the mechanical properties of the commonly used MEMS materials. One of the most important properties for MEMS is the Young''s modulus. This work describes the direct comparison of two methods often used for measuring the Young''s modulus of thin film materials using micro-cantilever test structures: a load-deflection method and a resonant frequency method. The comparison was carried out for a range of materials, different cantilever geometries as well as for single and multilayer materials. It was found that both methods produce results that agree with each other and also agree with the values most often given in the literature. [Copyright &y& Elsevier]