Surface micromachined capacitive accelerometer with laterally movable electrode
(off-plane accelerations):

Basic features:

• Device consists of a surface micromachined capacitive sensing cell that is hermetically sealed at the wafer level using a bulk micromachined 'cap' wafer
• Mechanical structure is formed from polysilicon using masking and etching
• Can be modelled as two stationary plates with a movable electrode in between
• Centre plate can be deflected from its rest position by subjecting the system to acceleration
• When the centre plate deflects, the distance from it to one fixed plate will increase by the same amount that the distance to the other plate decreases
• Change of distance is a measure of acceleration.