Piezoelectric Laminate Oxygen-18 Isotope Enrichment
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Solution Overview
Problem
Existing piezoelectric films made from perovskite-type oxides, such as PZT, face issues with stability and long-term reliability due to oxygen deficiency, leading to decreased dielectric breakdown voltage and piezoelectric constant when insulating layers are used to compensate for oxygen pores.
Innovation Solution
Incorporating an excess of oxygen-18 (18O) into the piezoelectric film, specifically a Pb-containing perovskite-type oxide, to enhance dielectric breakdown voltage without reducing the piezoelectric constant, by using a sputtering process that includes 18O in the film-forming gas, resulting in a piezoelectric laminate with improved structural stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an insulating layer is provided between the piezoelectric film and the electrode to increase the dielectric breakdown voltage, then the dielectric breakdown voltage is improved, but the piezoelectric constant is decreased
Solution Approach 1:
The patent changes the chemical composition parameter of the piezoelectric film by incorporating oxygen-18 isotope, transforming the film's properties to achieve both high dielectric breakdown voltage and maintained piezoelectric constant without requiring additional insulating layers
Solution Approach 2:
The patent creates a composite piezoelectric film structure containing both oxygen-16 and oxygen-18 isotopes, where the oxygen-18 enrichment provides dielectric stability while maintaining the perovskite structure's piezoelectric properties
2Reliability
If a metal oxide layer is provided to compensate for oxygen pores in the piezoelectric film, then the piezoelectric characteristics are suppressed from deteriorating, but the piezoelectric constant is decreased
Solution Approach 1:
The patent changes the isotopic composition of oxygen in the piezoelectric film, enriching it with oxygen-18, which fundamentally alters the film's resistance to oxygen deficiency without requiring compensatory metal oxide layers
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 increased ratio of 18O in the piezoelectric film suppresses oxygen defects, thereby improving the dielectric breakdown voltage and maintaining the piezoelectric constant, enhancing the long-term reliability of the piezoelectric element.
Implementation Method 1
using a sputtering process that includes 18O in the film-forming gas
Implementation Method 2
A piezoelectric body consisting of a perovskite-type oxide is applied as a piezoelectric film in a piezoelectric element
Data Source
AI summary
There is provided a piezoelectric laminate including, in the following order, a lower electrode layer and a piezoelectric film containing a Pb-containing perovskite-type oxide, in which the piezoelectric film contains an oxygen atom 18O having a mass number of 18 in oxygen as a constituent element in excess of a natural abundance ratio. There are also provided a piezoelectric laminate, a piezoelectric element, and a manufacturing method for a piezoelectric laminate.