Patent ID: 8836055

Claim:
A device comprising: a micro-electro-mechanical system (MEMS) device comprising: a movable element; and a fixed element, wherein the movable element and the fixed element form two capacitor plates of a capacitor, with an air-gap between the movable element and the fixed element acting as a capacitor insulator of the capacitor, and wherein the fixed element comprises: a first silicon-containing layer comprising a rugged surface having a root mean square deviation greater than about 10 nm; and a second silicon-containing layer adjoining the first silicon-containing layer, wherein one of the first silicon-containing layer and the second silicon-containing layer comprises polysilicon, and another one of the first silicon-containing layer and the second silicon-containing layer comprises amorphous silicon, and wherein a first surface of the first silicon-containing layer has a smaller roughness than the rugged surface, with the first surface of the first silicon-containing layer contacting a second surface of the second silicon-containing layer.