An exemplary method for forming gaps in a micromechanical device includes providing a substrate. A first material layer is deposited over the substrate. A sacrificial layer is deposited over the first material layer. A second material layer is deposited over the sacrificial layer such that at least a portion of the sacrificial layer is exposed. The exposed portion of the sacrificial layer is etched by dry etching. The remaining portion of the sacrificial layer is etched by wet etching to form gaps between the first material layer and the second material layer. One or more bulges are formed at one side of the second material layer facing the first material layer, and are a portion of the sacrificial layer remaining after the wet etching.