Piezoelectric Bonded Body Surface for Lower SAW Propagation Loss
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing surface acoustic wave elements, particularly in the range of 0.3 to 6.0 GHz, have a limited Q value due to propagation losses in the surface region of the piezoelectric material layer, which is not significantly improved by conventional polishing techniques.
Innovation Solution
A bonded body comprising a piezoelectric material layer with an argon atom-containing layer exposed on its second main surface, formed by argon ion trimming, which reduces propagation losses and enhances the Q value when an electrode is applied.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional polishing techniques are applied to the piezoelectric material layer, then the surface smoothness is improved, but the Q value remains limited due to propagation losses in the surface region
Solution Approach 1:
The patent changes the surface treatment method from conventional mechanical polishing to ion beam processing (argon ion trimming). This parameter change in the processing method creates a different surface structure that preserves the argon atom-containing layer, which reduces propagation losses and improves the Q value while maintaining adequate surface smoothness for acoustic wave propagation
Solution Approach 2:
The patent replaces the mechanical polishing system with an ion beam processing system. Instead of using mechanical abrasives and polishing pads, argon ions are used to trim the surface, which removes damaged layers and exposes the argon atom-containing layer without causing the same propagation losses associated with mechanical polishing
2Reliability
If the piezoelectric material substrate is thinned to improve surface acoustic wave properties, then the frequency characteristics are improved, but propagation losses increase in the surface region
Solution Approach 1:
The patent applies local quality by creating a specific surface structure with an exposed argon atom-containing layer at the surface region. This localized modification at the surface (where propagation losses occur) reduces energy loss without requiring changes to the bulk material properties or overall device structure
Solution Approach 2:
The argon atom-containing layer acts as an intermediary between the piezoelectric material and the external environment. This layer, created and preserved through ion beam processing, mediates the interaction at the surface to reduce propagation losses while allowing the thinned substrate to maintain its improved frequency characteristics
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 Q value of the acoustic wave element is considerably improved by exposing the argon atom-containing layer, leading to reduced propagation losses and enhanced frequency characteristics.
Implementation Method 1
the present inventors have variously studied the processing methods of the surface of the piezoelectric material substrate and tried ion trimming with argon ion. As a result, a thin processing denatured layer was formed on the surface of the piezoelectric material layer
Data Source
AI summary
A bonded body has a supporting substrate and a piezoelectric material layer bonded with the supporting substrate. The piezoelectric material layer has a first main surface bonded with the supporting substrate and a second main surface on the opposite side of the first main surface. The piezoelectric material layer has an argon atom-containing layer exposed at the second main surface.