Panasonic Corporation

Panasonic Electric Works Co., Ltd.

Norihiro Yamauchi

Tomoaki Matsushima

Koichi Aizawa

Yoshiki Hayasaki

Takaaki Yoshihara

Takeo Shirai

Atsushi Suwa

Junya Ogawa

Koji Sasabe

Futoshi Nishimura

Sibei Xiong

A seed layer having a predetermined pattern is formed on a side of one surface of a second substrate, and a ferroelectric layer is formed on the side of the one surface of the second substrate. A lower electrode is formed on the ferroelectric layer, and the lower electrode and a first substrate are bonded via a bonding layer. A laser beam with a predetermined wavelength is irradiated from a side of other surface of the second substrate to transfer a ferroelectric film, which overlaps with the seed layer, of the ferroelectric layer and the seed layer onto the side of said one surface of the first substrate. The laser beam passes through the second substrate, is reflected by the seed layer, and is absorbed by a second portion of the ferroelectric layer. The second portion does not overlap with the seed layer.

Method for manufacturing ferroelectric device

A bandpass filter includes a combination of a BAW filter and a patterned planar filter with stubs. The BAW filter is composed of a plurality of piezoelectric resonators to give a specific frequency bandpass, while the planer filter is configured to attenuate frequencies near and outside the bandpass. The resonators are connected in a ladder configuration between a first signal transmission path and a ground. The planar filter includes a strip line formed on a dielectric layer to define a second signal transmission path. The BAW filter and the planar filter are formed on a common substrate with the first and second transmission paths connected to each other. The BAW filter, in combination with the patterned planar filter added with the stub, can improve a deep near-band rejection inherent to the BAW filter, exhibiting an excellent out-of-band rejection over certain adjacent frequency ranges outside of the bandpass, and therefore give a sharp and wide bandpass.

Bandpass filter and process of fabricating the same

Growing community of inventors

Osaka, Japan

Norihiro Yamauchi