Patent ID: 7998829

Claim:
A method to manufacture a semiconductor structure, comprising: removing a portion of a semiconductor material using an electrochemical etch to form a first cavity that extends at least about one micron or greater below the surface of the semiconductor material, a second cavity that extends at least about one micron or greater below the surface of the semiconductor material, wherein the first cavity is isolated from the second cavity, a first protrusion is between the first cavity and the second cavity, and the semiconductor material comprises silicon; performing a thermal oxidation to convert a portion of the silicon of the semiconductor material to silicon dioxide; and forming a first dielectric material over the first cavity, over the second cavity, over at least a portion of the semiconductor material, and over at least a portion of the first protrusion; wherein the electrochemical etch is preceded by an etch to form a cavity wherein a width of a lower portion of the cavity is substantially less than a width of an upper portion of the cavity.