A bridge-type piezoresistive accelerometer using merged epitaxial lateral overgrowth for thin silicon beam formation

Merged epitaxial lateral overgrowth (MELO) of silicon has been used to form 10 μm ± 0.5 pm thick, 420 μm long, and 170 μm wide single-crystal silicon beams for a four-bridge piezoresistive accelerometer. Buried SiO ₂ stripes are used to produce the near-perfect backside etch-stop for the silicon membrane, while the topside thickness control is established by the growth rate of 0.1 μm min ^-1. The MELO membrane technique produces an accelerometer that has low-doped high-quality single-crystal silicon beams. The measured sensitivity is 287 μV V ^-1 g ^-1, which is about twice that for a similar device, and the non-linearity is less than 4% up to 30g of acceleration.