Designing thermal MEMS on a system level

In this paper, a systematic method for designing a basic thermal MEMS design is discussed using the example of a thermal micromechanical mirror developed by MIET. The mirror is made with microelectronic technology and consists of two movable bimorph structures made of aluminum and silicon dioxide. A reflective element with an aluminumcoated surface is attached to the movable beams. The movable beams are fixed to a silicon substrate and are controlled by applying а voltage to electrical heating elements formed inside the movable beams. Heating causes uneven expansion of the materials that make up the beams, which in turn causes the structure to move. The proposed design process involves algorithmic design using three developed models to determine the initial parameters of the thermal actuator, its static and dynamic characteristics, and the response to the control action. The use of such an algorithm in the design flow allows for a quick selection of the basic geometric and physical parameters that should ensure that the actuator has the required performance and characteristics. This significantly reduces the time taken during the initial design phase of the device.