Micro-triboelectric generator for zero-power shock detection

This work shows zero-power shock sensing for the combination of a micro-triboelectric generator and MEMS electrostatic actuator system where the mechanical shock to the generator causes it to produce voltage, this voltage is used to actuate a Micro-Electro-Mechanical-system (MEMS) switch. For the first time, we present the fabrication process of a Triboelectric-Nano-Generator (TENG) with MEMS technology. The MEMS-TENG has a suspended 1.5 mm × 1.5 mm plate separated by 2 μm from the substrate. The generator is a triboelectric transducer made of a suspended Al micro-plate above a polyimide (PI) thin layer that is covered by another Al layer in the back. In case the shock is sufficiently strong, the micro-plate hits its substrate. As a result of the impact, electrification happens and PI gets negatively charged, while the Al gets positively charged. Connecting the generator to a MEMS switch, we use the generated voltage to actuate a MEMS switch. The TENG was able to supply voltage difference up to 0.4 V at 2.3g. We use the MEMS-TENG to actuate a cantilevered MEMS switch (500 × 20 × 2 μm) separated by a 2 μm gap from a fixed bottom electrode. Triboelectric generators are known for high voltages and low currents, which makes them ideal for integration with MEMS electrostatic devices that require ultra-low power to operate. Our feasibility study opens doors to billions of innovative devices that can be created from this synergistic combination.