Performance Of Micro One-sided Straight-leg Beam Resonator And Cascade V-Shape Thermal Actuator

As the power producer, the microactuator is an important part of microelectromechanical systems, which used as the conversion of energy, motion and force producing. The function and performance of MEMS are deeply affected by the micro-actuator's output ability of displacement and force. In this dissertation, the structure design, driving mechanism, analysis modeling and performance testing of laterally driven resonantor suspended with one-side straight-leg beams,Π-shape beam and cascade V-shape beam electrothermal actuators are studied. The effects of the structure parameters of above microactuators on the produce ability of displacement and force are discussed. Some MEMS executors are developed besed on those microactuators. The main work is as follows.The silicon surface micromachining process of three layers polysilicon is developed in cooperated with Institute of Microelectronics of Peking University. And most of tested microactuators, several type microvibromotors made use of the microactuators were fabricated using the surface micromaching process. Appropriate measures have been taken in the design respectively for the problems, that in some parts of microvibromotor the friction hoped to be increased for motion and force transfer, and for some other parts the friction hoped to be decreased in order to make the movement easily. A nano actuator driven by V-shape beam electrothermal actuators is designed and fabricated using standard bulk silicon micromachining process and two stages lever mechanism. The in and out displacements simultaneously comparison method is used with static teeth rules for proving the nano motion and measuring the nano displacement.The lateral vibration of microresonator suspended with one-side straight-leg beams is simple modeled in a superfluous system with three unknown variables. Methods are given to calculate the lateral displacement, spring coefficient and resonant frequency. Comparing with the microresonator suspended with double-side straight-leg beams that is a superfluous system with five unknown variables, it is found that the mechanical properties of the former are quite different with that of later. So it is not correct in the view of physics that calculate the former performance using the mechanical analysis model of later which has been commonly used before.It is clearly different with the microresonator suspended with double-side straight-leg beams from the analysis results that the spring coefficient, resonant frequency and lateral displacement could be changed with the variation of distance between the two straight-leg beams in microresonator suspended with one-side straight-leg beams. After the distance over to a value, the change of all the above three variable is very small and tends to a fixed numble. Similarly, the resonant frequency also can be changed with the variation of beam thickness in later, but there is no this phenomenon in the former. So an explanation is given according to the different redundance for the two different superfluous systems.The laterally deflection of cascade V-shape beam electrothermal actuators is modeled statically in a superfluous system with three unknown variables. And the iteration algorithm is set up for all type force calculating in anchors. The effects of the structure parameters on the produce ability of displacement are discussed. It is found that the difference is obviously between single and discussed cascade V-shape beam electrothermal actuators. Because the maximum deflection is taken place in 0.04 rad bending angle for the former, but for the later one the bending angle is 0.19 tad. There is no relation between deflection and beam thickness for both of them. In the same beam length and width conditions, the comparing results between the single V-shape andΠ-shape beam electrothermal actuators showes that the force and displacement produce ability for both of them are quite different at three different regions in the figure of displacement and force output.A measuring system is set up for obtaining the performance of four type silicon microactuator. The resonance frequencies tested from several microresonators suspended with one-side straight-leg beams are coincidence with the analytic results. The biggest relative error between them is below 12%. The output displacement of both cascade V-shape andΠ-shape beam electrothermal actuators before burnt down is very close to the theoretical results at 800℃, and the relative error is in 6.7%. So it gives an indirect prove that the statical model for laterally deflection of cascade V-shape beam electrothermal actuators is correct. The testing results also shows the nano motion could be achieved with the bulk nano actuator driven by single V-shape beam electrothermal actuator and the platform can be controlling moved in nano step. It is shown in experiment that the function of part microvibromotors made use of the above microactuators has come true, but the performance still need to be improved.