Murata Manufacturing Co., Ltd.

National Institute of Advanced Industrial Science and Technology

Yasuhiro Aida

Keiichi Umeda

Shinsuke Ikeuchi

Morito Akiyama

Fumiya Kurokawa

Masayuki Suzuki

Seiji Umezawa

Hiroshi Yamada

Masato Uehara

Takaaki Mizuno

Toshimi Nagase

Daiki Murauchi

An ultrasonic transducer includes first and second acoustic transducers and a housing with a bottomed tubular shape. The second acoustic transducer includes an annular section supporting a second membrane section and contacting an entire periphery of the second membrane section, and an acoustic matching plate facing the second membrane section and spaced apart from the second membrane section. The acoustic matching plate is connected to a surrounding wall portion defining a sealed space with the housing. An ultrasonic transmission path sandwiched between the first membrane section and the second membrane section is provided in the sealed space. A maximum inner width of the ultrasonic transmission path is smaller than a maximum inner width of the surrounding wall portion.

Ultrasonic transducer

A piezoelectric element that includes a substrate, a lower electrode layer on the substrate, an intermediate layer on the lower electrode layer, and an upper electrode layer on the intermediate layer. The intermediate layer includes a first piezoelectric layer including an aluminum nitride as a main component thereof and located between the lower electrode layer and the upper electrode layer, a first buffer layer including an aluminum nitride as a main component and located between the first piezoelectric layer and the upper electrode layer, a first intermediate electrode layer located between the first buffer layer and the upper electrode layer, and a second piezoelectric layer located between the first intermediate electrode layer and the upper electrode layer.

Piezoelectric element, and resonator using piezoelectric element

A gallium nitride structure that includes: a substrate; a gallium nitride layer opposed to the substrate and containing gallium nitride as a main component thereof; and a first electrode between the gallium nitride layer and the substrate. The first electrode includes at least one hafnium layer containing a single metal of hafnium as a main component thereof, and the at least one hafnium layer is in contact with the gallium nitride layer.

Gallium nitride structure, piezoelectric element, method of manufacturing piezoelectric element, and resonator using piezoelectric element

A piezoelectric film that includes crystalline AlN; at least one first element partially replacing Al in the crystalline AlN; and a second element doping the crystalline AlN and which has an ionic radius smaller than that of the first element and larger than that of Al.

Piezoelectric thin film and piezoelectric vibrator

A method for manufacturing a resonator that effectively addresses variations in resistivity for each wafer. The method for manufacturing a resonator includes forming a Si oxide film on a surface of a degenerated Si wafer, where the Si oxide film has a thickness set that is based on the doping amount of impurity in the degenerated Si wafer.

Growing community of inventors

Nagaokakyo, Japan

Yasuhiro Aida