Vibration rectification in silicon micromachined accelerometers

The phenomenon of vibration rectification in silicon accelerometers is described. Examples of the effect are looked at for the case of piezoresistive silicon micromachined accelerometers. Quad-beam (doubly clamped) devices are compared to dual-beam (simple cantilever) devices. It is shown that for dual-beam accelerometers, the majority of vibration rectification can be attributed to simple quadratic nonlinearity of the accelerometer response and that the other rectification effects are at least an order of magnitude lower. The dual-beam devices perform substantially better than quad-beam devices. It is noted that this effect should be considered when applying these devices to DC measurements, especially when high levels of vibration may be present.<>