Patent ID: 6389902
Filing Date: 2002-05-21
Classification: B81B,B81C,H04R

Abstract:
A method of producing a micromechanical sensor, which comprises:providing a doped semiconductor wafer; applying an epitaxial layer on the wafer and ensuring that at least a portion of a region of the epitaxial layer that faces the wafer is doped such that a jump in a charge carrier density occurs at an interface between the wafer and the epitaxial layer; etching ventilation openings through the epitaxial layer; applying at least one sacrificial layer, at least one spacer layer, and a membrane on the epitaxial layer; etching an opening in a rear of the wafer using an etching method such that the etching progresses towards a top of the wafer and stops at an interface between the wafer and the epitaxial layer by a changed charge carrier concentration; and removing the at least one sacrificial layer with an etchant to expose the ventilation openings and to form a membrane, a counterelectrode disposed underneath the membrane, and a cavity disposed between the membrane and the counterelectrode, the ventilation openings connecting the cavity to the opening in the rear of the wafer.