Wafer-level self-packaged MEMS infrared emitters with high-emissivity black silicon surface.

Infrared (IR) gas sensors have an urgent demand for high-reliability MEMS IR emitters. In this study, a wafer-level self-packaged MEMS IR emitter (SPIRE) has been designed and manufactured to enhance the durability of devices in high temperatures and ambient air. In the state-of-the-art design, Pt-wire heating and temperature sensing elements were fabricated onto a silicon (Si) membrane and vacuum-sealed within a glass cavity utilizing the Si-glass anodic bonding technique. Additionally, a black-Si nanostructure was prepared on the opposite side of the Si membrane to enhance IR light emissivity. The electrical-thermal-mechanical properties were simulated using COMSOL Multiphysics to optimize the structural design. The devices were fabricated through wafer-level MEMS processing techniques. Testing results demonstrated that the SPIREs were capable of achieving a light-emitting power intensity of 172 mW/Sr/µm at a peak wavelength of 6.1 µm and a 3-dB bandwidth of 52 Hz, corresponding to a surface temperature of 400 °C at a driving power of 850 mW. Long-term reliability was assessed through an accelerated aging test and a life prediction method. The estimated lifespan of the SPIREs can reach 10 years at a working temperature of 500 °C.