Arrays of silicon cantilevers for detecting high-G rapidly varying acceleration profiles

This work presents the first experimental study on the effectiveness of single-crystal silicon (SCS) cantilever arrays as contact-based high-G sensors in digital MEMS accelerometers. Unlike conventional designs, a digital scheme is employed where detection of a specific acceleration level is associated with a group of silicon cantilevers, which deflect and make solid-to-solid silicon contacts with the substrate. This scheme is especially useful in applications where a high-G rapidly changing acceleration profile needs to be detected with a high confidence level. The proposed designs have been successfully demonstrated up to 45,000 g, which is commonly found in impact and pyroshock phenomena, such as in multistage rocket launches and earth penetrating weapons. The arrays of beams offer high redundancy in the measured data, which is critical when used in events with severe consequences. The fabricated devices were tested using a modified Kolksy bar setup and found to have contact resistances in the order of ~3.2±3 kΩ. Depending on the applied acceleration profile, contact bouncing is observed during testing.