Fabrication of an integrated voltage sensing capacitor

摘要

A capacitor for sensing the substrate voltage is efficiently and economically realized simply by isolating a portion or segment of the metal layer that normally covers the heavily doped perimetral region of electric field equalization and, in correspondence of such a metal segment isolated by the remaining portion, by not removing preventively the isolation dielectric layer of silicon oxide from the surface of the semiconductor substrate, as it is normally done on the remaining portion of the perimetral edge region before depositing the metal. The unremoved layer of isolated silicon oxide (12) becomes the dielectric layer of the so constituted capacitor, a plate of which is the heavily doped perimetral region (4) that is electrically connected to the substrate (drain or collector region) while the other plate is constituted by the segment of metal (4'), isolated from the remaining metal layer defined directly over the heavily doped perimetral region (4). <IMAGE>