An accelerometer includes a planar proof mass mounted to a fixed substrate so as to be linearly moveable in an out-of-plane sensing direction in response to an applied acceleration. The proof mass includes first and second sets of moveable capacitive electrode fingers extending from the proof mass perpendicular to the sensing direction in a first in-plane direction and laterally spaced in a second in-plane direction perpendicular to the sensing direction. The moveable capacitive electrode fingers interdigitate with corresponding sets of fixed capacitive electrode fingers mounted to the substrate. The first set of fixed fingers has a thickness less than a thickness of the first set of moveable fingers; and wherein the second set of fixed fingers has a thickness greater than a thickness of the second set of moveable fingers.