Rf360 Singapore Pte. Ltd.

Snaptrack Incorporated

Christian Ceranski

Maximilian Schiek

Willi Aigner

Tomasz Jewula

Bernhard Bader

Benno Blaschke

Günter Scheinbacher

A bulk acoustic wave (BAW) device comprises a layer stack including first and second electrodes, a first piezoelectric layer between the electrodes, and a second piezoelectric layer between the first piezoelectric layer and the second electrode. A polarization of a crystal structure of the second piezoelectric layer is opposite to a polarization of a crystal structure of the first piezoelectric layer to achieve higher order resonant frequencies in the BAW device by means other than merely thinning layers in the layer stack. In some examples, the BAW device is a two-terminal device and does not include a metal layer configured to be a third electrode. In some examples, the BAW device includes at least one intermediate layer between the first and second piezoelectric layers, and a total combined thickness of the at least one intermediate layer is less than 4% of a total thickness of the layer stack.

Bulk acoustic wave (BAW) device with oppositely polarized piezoelectric layers for higher order resonance and method of manufacture

An apparatus is disclosed for implementing a microacoustic filter with a cavity stack. In an example aspect, the apparatus includes a microacoustic filter with an electrode structure, a cavity stack, a buffer layer, and a piezoelectric layer. The cavity stack comprises a conductive layer, a substrate layer, and at least two pillars extending past a plane defined by a surface of the substrate layer and towards the conductive layer to form a cavity between the substrate layer and the conductive layer. The buffer layer is disposed between the conductive layer of the cavity stack and the electrode structure. The piezoelectric layer is disposed between the buffer layer and the electrode structure.

Microacoustic filter with a cavity stack

A method for forming an aluminum nitride layer () comprises the provision of a substrate () and the forming of a patterned metal nitride layer (). A bottom electrode metal layer () is formed on the exposed portions () of the substrate. An aluminum nitride layer portion () grown above the exposed portion () of the substrate () exhibits piezoelectric properties. An aluminum nitride layer portion () grown above the patterned metal nitride layer () exhibits no piezoelectric properties (). Both aluminum nitride layer portions () are grown simultaneously.

Method for forming an aluminum nitride layer

In order to improve heat dissipation from electrical components with heat-generating component structures, it is proposed to provide a radiation layer with a large surface in the area of the component structures. Preferably, the radiation layer is very heat-conductive or in heat-conductive connection with the component structures.

Growing community of inventors

Munich, Germany

Christian Ceranski