US Patent 7656252 - MEMS resonator with tapered electrode

http://www.freepatentsonline.com/7656252.html

This patent is from Seiko Epson and teaches a MEMS resonator less susceptible to etching residue and current leakage by providing a tapered contact electrode. Claim 1 reads:

1. A micro-electro-mechanical-system resonator, comprising:

a substrate;

a fixed electrode formed on the substrate; and

a movable electrode, arranged facing the fixed electrode and driven by an electrostatic attracting force or an electrostatic repulsion force that acts on a gap between the fixed electrode and the movable electrode;

wherein the fixed electrode has a tapered surface on a side thereof.