Electrical contact for a mems device and method of making

摘要

A method for making a subsurface electrical contact (34) on a micro-electrical-mechanical-systems (MEMS) device (10). The contact (34) is formed by depositing a layer of polycrystalline silicon (34) onto a surface (16) within a cavity (20) buried under a device silicon layer (24). The polycrystalline silicon layer (34) is deposited in the cavity (20) through holes (30 and 32) etched through the device silicon (24) and reseals the cavity (20) during the polycrystalline silicon deposition step. The polycrystalline silicon layer (24) can then be masked and etched, or etched back to expose the device layer (24) of the micromachined device (10). Through the layer of polycrystalline silicon (34), a center hub (18) of the device (10) may be electrically contacted.