Patent ID: 8686519

Claim:
A MEMS accelerometer comprising: a substrate; a membrane suspended over an opening which extends through the substrate, wherein the membrane defines a first electrode layer; and a second electrode layer provided over the membrane and spaced from the membrane, wherein a force applied to the membrane normally to the membrane causes a change in spacing between the membrane and the second electrode layer; wherein the second electrode layer comprises a stack of a lower insulator, a conductor and a top insulator, and the conductor is patterned to define at least four independent electrodes arranged as a first pairs of opposing electrodes and a second pair of opposing electrodes; the first pair of opposing electrodes disposed along a first axis and the second pair of opposing electrodes disposed along a second axis, wherein the first axis is orthogonal to the second axis and wherein the first pair of opposing electrodes and the second pair of opposing electrodes are mechanically one unity and electrically split from each other, such that tilting of the membrane about the first axis and the second axis can be detected as well as normal-direction movement of the membrane, and wherein the membrane defines a single electrode.