Air-gap type FBAR, method for fabricating the same, and filter and duplexer using the same

摘要

An air-gap type thin film bulk acoustic resonator (FBAR) and method for fabricating the same. Also disclosed are a filter and a duplexer employing the air-gap type FBAR. The air-gap type FBAR includes: a first substrate (200) having a cavity part (210) at a predetermined region on its upper surface; a dielectric film stacked on the upper part of the first substrate; a first air gap formed between the first substrate and the dielectric film (220); a stacked resonance part (230) including a lower electrode/piezoelectric layer/upper electrode formed on the upper part of the dielectric film; a second substrate (240) having a cavity part at a predetermined region on its lower surface and joined to the first substrate; and a second air gap (250) formed between the stacked resonance part and the second substrate. A thin film of predetermined thickness made of a liquid crystal polymer (LCP) may be used as the dielectric film.