Image Number 15 for United States Patent #8115272.
An apparatus includes a semiconductor layer (2) having therein a cavity (4). A dielectric layer (3) is formed on the semiconductor layer. A plurality of etchant openings (24) extend through the dielectric layer for passage of etchant for etching the cavity. An SiO2 pillar (25) extends from a bottom of the cavity to engage and support a portion of the dielectric layer extending over the cavity. In one embodiment, a cap layer (34) on the dielectric layer covers the etchant openings.