Patent ID: 8076245

Claim:
A process comprising: forming a dual thin film structure comprising a lower membrane and an upper thin film structure, wherein the lower membrane is positioned beneath the upper thin film structure and above a substrate; placing an electrode on the upper thin film structure after forming the dual thin film structure, wherein the electrode is positioned above the upper thin film structure; applying a metal-oxide semiconductor (MOS) material onto the dual thin film structure after placing the electrode on the upper thin film structure; after applying the MOS material onto the dual thin film structure, etching a portion of the substrate that is below the electrode, thereby removing the substrate but not the electrode or the MOS material, wherein the etching is performed from a side of the substrate opposite the lower membrane and upper thin film structure, and wherein the substrate etching is performed prior to etching of the upper thin film structure or etching of the lower membrane; after etching the portion of the substrate below the electrode, using etch removal of the upper thin film structure; and after the etch removal of the upper thin film structure, using etch removal of the lower membrane to form a metal-oxide semiconductor (MOS) device on the upper thin film structure such that the lower membrane is removed from an area directly beneath the electrode, such that the lower membrane protects the upper film structure from one or more substrate etching processes, and such that the etch removal of the upper thin film structure and the etch removal of the lower membrane creates an open structure such that a passageway extends through the lower membrane and the upper thin film structure; wherein the MOS material forms a low power sensor.