Electrothermal actuation is one of the main actuation mechanisms and has been employed to make scanning microelectromechanical systems (MEMS) mirrors with large scan range, high fill factor, and low driving voltage, but there exist long-term drifting issues in electrothermal bimorph actuators whose causes are not well understood. In this paper, the stability of an $\mathrm{Al}/{\mathrm{SiO}}_2$ bimorph electrothermal MEMS mirror operated in both static and dynamic scan mode has been studied. Particularly, the angular drifts of the MEMS mirror plate were measured over 90 h at different temperatures in the range of $50$ – $150$ °C. The experiments show that the temporal drift of the mirror plate orientation largely depends on the temperature of the electrothermal bimorph actuators. Interestingly, it is found that the angular drift changes from falling to rising as the temperature increases. An optimal operating temperature between $75$ °C to $100$ °C for the MEMS mirror is identified. At this temperature, the MEMS mirror exhibited stable scanning with an angular drift of less than $0.0001$ °/h.

The acceleration sensor with high g value is widely used in a variety of fields, including collision impact, aerospace, and defense security and thus is a key focus in the future. The sensor with a double-ended four-beam structure is investigated in this paper via finite element simulation analysis. The measurement sensitivity of the sensor can be improved by changing the position of the cantilever beam. Furthermore, transverse interference in the X-direction and Y-direction can be eliminated in theory through the layout of piezoresistors and the Wheatstone circuit. The simulation results show that the sensor's sensitivity is 2.6μV/g while its cross-sensitivity in the X-direction and Y-direction is 0%, indicating that the sensor's performance has been substantially improved.