Piezoelectric Element Orientation Control Layer
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Solution Overview
Problem
Forming a uniformly (100) plane-oriented piezoelectric layer on a large-area substrate is challenging due to variations in crystal orientation, leading to reduced piezoelectric performance in piezoelectric elements, especially when using KNN piezoelectric materials with Ir electrodes.
Innovation Solution
Incorporating a perovskite complex oxide orientation control layer containing potassium, sodium, calcium, and niobium, preferentially oriented in the (100) plane, between the electrode and the piezoelectric layer to maintain crystal orientation uniformity and enhance piezoelectric performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a KNN piezoelectric layer is formed on an Ir electrode, then the piezoelectric element can be manufactured, but the orientation of KNN crystals becomes disordered and piezoelectric performance is reduced
Solution Approach 1:
An orientation control layer is introduced as an intermediary between the Ir electrode and the KNN piezoelectric layer. This intermediate layer mediates the interaction between the electrode and piezoelectric material, preventing direct harmful contact while providing the necessary (100) plane orientation template for uniform crystal growth, thereby resolving the contradiction between manufacturability and performance
Solution Approach 2:
The orientation control layer is formed in advance before depositing the KNN piezoelectric layer. This preliminary action establishes the desired (100) plane orientation pattern on the electrode surface beforehand, ensuring that subsequent KNN crystal growth follows the predetermined orientation, thus preventing orientation disorder before it occurs
2Productivity
If a piezoelectric layer is formed on a large-area substrate (6-inch or larger wafer), then production capacity increases, but in-plane nuclear density distribution varies and uniform (100) plane-oriented film formation becomes difficult
Solution Approach 1:
The orientation control layer provides locally optimized (100) plane orientation characteristics across the entire large-area substrate surface. By treating each local region with the same orientation template, the layer ensures uniform crystal orientation throughout the large substrate area, enabling both high productivity and manufacturing precision simultaneously
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
The solution allows for uniform in-plane formation and preferential (100) plane orientation of the piezoelectric layer, independent of the underlying layer, thereby maintaining high piezoelectric performance and reducing the likelihood of performance degradation.
Implementation Method 1
the orientation control layer contains perovskite complex oxide containing potassium, sodium, calcium, and niobium and preferentially oriented in the (100) plane
Implementation Method 2
a piezoelectric layer capable of electromechanical conversion
Data Source
AI summary
A piezoelectric element includes a first and a second electrode, a piezoelectric layer between the first electrode and the second electrode, and an orientation control layer between the first electrode and the piezoelectric layer. The orientation control layer contains perovskite complex oxide containing potassium, sodium, calcium, and niobium and preferentially oriented in the (100) plane.