Micromachining for silicon microaccelerometer

In this paper, the concepts of "bulk" and "surface" micromachining are first presented. The fabrication techniques for realising silicon microaccelerometer using these two approaches are next presented. In both the cases, the acceleration is measured by detecting the change in the capacitance due to the deflection of an inertial mass called seismic mass or proof mass with respect to fixed plates. The relative merits of the two approaches are presented to show that inspite of the simplicity and low cost nature of bulk micromachining, the surface micromachining has gained popularity because of its versatility and suitability for integrating the surface micromachined sensors with the integrated circuits.