Channel for decreasing damping asymmetry

Abstract

The present invention relates micro-electromechanical systems (MEMS); in particular to a comb channel structure for decreasing damping asymmetry of comb electrodes used to measure movement of components with MEMS devices. The channel is formed by a series of recesses formed in the comb fingers of the comb electrodes, or in the cap or handle wafer adjacent to the comb fingers. The channel increases the cross sectional area of the path through which gas can move into or out of the space between the comb electrodes as the comb electrodes move with respect to one another. Thus, when there is a damping asymmetry caused by a difference in the distance between the comb electrode and the cap wafer, and the comb electrode and handle wafer, the channel is employed on the side of the comb electrode with the smaller distance to the adjacent wafer to reduce the damping asymmetry.