Presettable micromachined MEMS accelerometers

Rapidly emerging wireless distributed sensing applications such as seismic monitoring, civil structural safety, security, and military threat identification require small, inexpensive acceleration sensors with sensitivities limited by the background noise of the earth. As will be shown, this goal may only be attained through a low resonant frequency device with a presettable spring. This paper will discuss design techniques in the quest for this goal and a novel, mechanically micro-adjustable Z-axis deep reactive ion etched (DRIE) accelerometer sensor with a resonant frequency below 100 Hz. This accelerometer design will be capable of sub-micro-g sensitivities and has a simple, low cost fabrication process.