US Patent 9238581 Triple-axis MEMS accelerometer

An integrated circuit structure includes a triple-axis accelerometer, which further includes a proof-mass formed of a semiconductor material; a first spring formed of the semiconductor material and connected to the proof-mass, wherein the first spring is configured to allow the proof-mass to move in a first direction in a plane; and a second spring formed of the semiconductor material and connected to the proof-mass. The second spring is configured to allow the proof-mass to move in a second direction in the plane and perpendicular to the first direction. The triple-axis accelerometer further includes a conductive capacitor plate including a portion directly over, and spaced apart from, the proof-mass, wherein the conductive capacitor plate and the proof-mass form a capacitor; an anchor electrode contacting a semiconductor region; and a transition region connecting the anchor electrode and the conductive capacitor plate, wherein the transition region is slanted.