BAW Electrode Bridge Structure for High-Frequency Loss Reduction

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Solution Overview

Problem

Bulk Acoustic Wave (BAW) resonators operating at higher frequencies face challenges with increased electrical losses due to thinner electrodes and smaller resonating areas, which affect their performance in high-frequency communication applications.

Innovation Solution

The introduction of conductive bridge structures in BAW structures, which include a first electrode, a second electrode, and a piezoelectric layer, with conductive bridge structures extending laterally and in contact with central stripe areas of the electrodes, reducing electrical current flow and losses by allowing current to flow from the bridges to the electrodes, thereby minimizing ohmic resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If BAW resonators operate at higher frequencies, then the filtering performance is improved, but electrical losses increase due to thinner electrodes and smaller resonating areas

Engineering Contradiction:

Improveoperating frequencyVSAvoidelectrical loss

Core Design Contradiction:

SpeedVSLoss of energy

Solution Approach 1:

The electrode structure is segmented into multiple regions: a central stripe area and peripheral areas. Conductive bridge structures are selectively positioned to contact only the central stripe areas of both electrodes, creating a segmented current path that reduces overall electrical loss while maintaining the necessary resonating area for high-frequency operation

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Conductive bridge structures serve as intermediary elements between the first and second electrodes. These bridges provide low-resistance current pathways that bypass the high-loss thin electrode regions, thereby reducing electrical losses without compromising the high-frequency filtering performance

Inventive Principle:

Principle #24Intermediary (Mediator)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This configuration effectively reduces electrical losses in BAW resonators, enhancing their performance by minimizing current flow through the electrodes and maintaining low resistivity in the conductive bridges, thus improving their efficiency in high-frequency applications.

Implementation Method 1

a piezoelectric layer between the first electrode and the second electrode

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

conductive bridge structures extending laterally and in contact with central stripe areas of the electrodes, reducing electrical current flow and losses by allowing current to flow from the bridges to the electrodes

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentUS20240333251A1Bulk acoustic wave structures with conductive bridge structures

Publication Date: 2024.10.03 QORVO US INC

AI summary

A bulk acoustic wave (BAW) is provided. The BAW structure includes a transducer that includes a first electrode, a second electrode, a piezoelectric layer between the first electrode and the second electrode, and a conductive bridge structure extending in a lateral direction and in contact with the first electrode at a central stripe area of the first electrode.