Patent ID: 7396736

Claim:
A process for fabricating a magnetic sensor comprising: forming an epitaxial layer comprising at least one of Ge and SiGe alloy on a semiconductor substrate; forming a conductive layer on the epitaxial layer; etching two lateral trenches through the conductive layer, the epitaxial layer and into the semiconductor substrate to form a central stack defined by a portion of the conductive layer, a portion of the epitaxial layer, and a portion of the semiconductor substrate, with the portion of the epitaxial layer being exposed on two opposed lateral sides of the central stack; selectively removing part of the portion of the epitaxial layer to form a cavity bounded by the semiconductor substrate and the conductive layer, with the conductive layer forming a membrane; forming lateral spacers on the semiconductor substrate to close the cavity; doping the semiconductor substrate under the membrane with a dopant of a first type of conductivity to form a lower electrode of a capacitor; doping the membrane with a dopant of the first type of conductivity to form an upper electrode of the capacitor; and doping the semiconductor substrate exposed by the two lateral trenches with a dopant of a second type of conductivity to isolate the lower electrode of the capacitor.