MEMS switch is a movable device manufactured by means of semiconductor technology, possessing many incomparable advantages such as a small volume, low power consumption, high integration, etc. This paper reviews recent research of MEMS switches, pointing out the important performance indexes and systematically summarizing the classification according to driving principles. Then, a comparative study of current MEMS switches stressing their strengths and drawbacks is presented, based on performance requirements such as driven voltage, power consumption, and reliability. The efforts of teams to optimize MEMS switches are introduced and the applications of switches with different driving principles are also briefly reviewed. Furthermore, the development trend of MEMS switch and the research gaps are discussed. Finally, a summary and forecast about MEMS switches is given with the aim of providing a reference for future research in this domain.

Micro-electromechanical systems (MEMS) safety-and-arming (S&A) device shows great potential in munition miniaturization, and it can be seen as the symbol of the fourth generation of weapons systems. In this paper, the design, fabrication, and actuation performance of a silicon based S&A device is presented. It is a multilayer stacked device, which is composed of the cover plate, the actuation chip, and the barrel plate. The electro-thermal principle is investigated in MEMS scale. With 11 V driving voltages, the structure of V-shape actuator, pawl, and slider can generate 100 μm and 45 μm displacement, and realize pulling, disengaging, and reengaging to change the device from the safety position into armed position smoothly (550 μm displacement). The rack and interlock mechanism formed by the pawl and slider gives the device the features of linear output displacement, low power consumption, input signal recognition, and sustained displacement. The 20,000 g setback acceleration is applied, and no structure damage can be found after the impact, which indicates the good anti-load ability of the MEMS S&A device. In order to solve the contradiction between the functional structure and the fabrication process, different structures are designed separately on different wafers. Both silicon and SOI wafers are used in the fabrication process, and the S&A device has been minimized into 8.5 mm × 8.5 mm × 0.8 mm successfully.

With the development of small size and high energy output of initiators, how to improve the safety of the system becomes an urgent problem. Therefore, a novel Micro-electro-mechanical System (MEMS) initiator with a built-in safety-and-arming (S&A) device is introduced in this paper. The MEMS initiator is composed of the MEMS ignitor and the MEMS S&A device. A movable barrier with a fire hole is controlled by the MEMS S&A device. Driven by the electro-thermal principle, the barrier can be moved backward or forward to open or close the fire channel, and the status conversion between the armed mode and the safe mode can be realized. The test results show that under specific control signals, the MEMS S&A device can generate 1 mm output displacement. Under the armed mode, the flame can burst out from the fire channel when stimulated by 64 V pulse voltage. Under the safe mode, the barrier hit by the flame can stay intact, and the explosion energy is blocked in the fire channel successfully. The silicon wafer and silicon-on-insulator wafer are used to fabricate the MEMS S&A device. Integrated with the MEMS ignitor, the total chip size is 11 × 12 × 1.2 mm³.

Considering the safety of ammunition, safety and arming (S&A) devices are usually designed in pyrotechnics to control energy transfer through a movable barrier mechanism. To achieve both intelligence and miniaturization, electrothermal actuators are used in MEMS S&A devices, which can drive the barrier to an arming position actively. However, only when the actuators’ energy input is continuous can the barrier be stably kept in the arming position to wait for ignition. Here, we propose the design and characterization of a double-layer electrothermal MEMS S&A Device with a bistable mechanism. The S&A device has a double-layer structure and four groups of bistable mechanisms. Each bistable mechanism consists of two V-shape electrothermal actuators to drive a semi-circular barrier and a pawl, respectively, and control their engagement according to a specific operation sequence. Then, the barrier can be kept in the safety or the arming position without energy input. To improve the device’s reliability, the four groups of bistable mechanisms are axisymmetrically placed in two layers to constitute a double-layer barrier structure. The test results show that the S&A device can use constant-voltage driving or the capacitor–discharge driving to drive the double-layer barrier to the safety or the arming position and keep it on the position passively by the bistable mechanism.