Piezoelectric Device Crystal Orientation Control
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Solution Overview
Problem
Piezoelectric devices with lead zirconate titanate (PZT) layers in liquid jet heads face variations in piezoelectric characteristics due to crystal orientation changes with environment and process conditions, affecting reliability and uniformity.
Innovation Solution
A piezoelectric device with a PZT layer having a half-width of the (100) plane measured by X-ray diffraction rocking curve between 10 and 25 degrees, and a sum of (110) and (111) orientations between 3% and 50%, ensuring consistent piezoelectric characteristics through precise crystal orientation control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a PZT layer is used in a piezoelectric device, then piezoelectric characteristics can be achieved, but the characteristics vary significantly depending on crystal orientation
Solution Approach 1:
The patent applies parameter changes by controlling the half-width of the (100) plane peak in the X-ray diffraction rocking curve to be 10 degrees or more and 25 degrees or less. This specific parameter range ensures that the piezoelectric layer has appropriate crystal orientation characteristics, reducing variation in piezoelectric properties while maintaining the necessary crystal structure for functionality.
2Device complexity
If the electric field application direction is kept constant in a stacked structure, then device simplicity is maintained, but piezoelectric characteristics vary depending on crystal orientation
Solution Approach 1:
The patent applies local quality by specifying that the PZT layer should have a half-width of the (100) plane peak of 10 degrees or more and 25 degrees or less in the X-ray diffraction rocking curve. This local crystal orientation control within the piezoelectric layer ensures uniform piezoelectric characteristics even with constant electric field application direction in the stacked structure.
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 provides a piezoelectric device and liquid jet head with uniform and reliable piezoelectric characteristics, reducing the impact of crystal orientation variations and ensuring high reliability across different conditions.
Implementation Method 1
a piezoelectric layer formed over the lower electrode and including lead zirconate titanate
Data Source
AI summary
A piezoelectric device including: a substrate; a lower electrode formed over the substrate; a piezoelectric layer formed over the lower electrode and including lead zirconate titanate; and an upper electrode formed over the piezoelectric layer, the lead zirconate titanate having a half-width of a peak of a (100) plane measured by an X-ray diffraction rocking curve method of 10 degrees or more and 25 degrees or less.