Piezoelectric Resonator Temperature Compensation via SiOx Layer

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Current piezoelectric acoustic resonators face challenges in achieving flexible temperature compensation, as the temperature coefficient of sound velocity in existing compensation layers cannot be effectively adjusted, limiting design flexibility and performance across varying temperature ranges.

Innovation Solution

A piezoelectric acoustic resonator with an adjustable temperature compensation capability is achieved by using a single-layer temperature compensation layer made of Si x O y materials, where the silicon-oxygen atomic ratio x:y is adjusted to control the temperature coefficient of sound velocity, allowing for reverse compensation of frequency shifts caused by the electrodes and piezoelectric layer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a piezoelectric acoustic resonator is operated at high temperature (e.g., 150°C or higher), then the resonant frequency stability deteriorates due to temperature-induced frequency shifts, but adding traditional temperature compensation components increases device complexity and size

Engineering Contradiction:
Improveresonant frequency stabilityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the temperature compensation function with the piezoelectric resonator itself by integrating a compensation electrode structure into the resonator. This merging eliminates the need for separate temperature compensation components, thereby maintaining resonant frequency stability at high temperatures while avoiding increased device complexity

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent modifies the electrical parameters of the resonator by introducing a compensation electrode that applies a controlled DC voltage. This voltage compensates for the temperature-induced frequency shifts by altering the electrical characteristics of the piezoelectric material, thus maintaining frequency stability without adding complex mechanical structures

Inventive Principle:
Principle #35Parameter changes

2Reliability

If a piezoelectric acoustic resonator is operated at high temperature, then the resonant frequency shifts occur, but adding external temperature compensation circuits increases the overall size of the device

Engineering Contradiction:
Improveresonant frequency stabilityVSAvoiddevice size
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The compensation electrode is nested within the existing resonator structure, utilizing the same packaging cavity and structural space. This nesting approach allows the temperature compensation function to be embedded within the resonator itself, avoiding any increase in the overall device volume while maintaining frequency stability

Inventive Principle:
Principle #7Nested doll (Nesting)

3Device complexity

If the resonator structure is simplified to reduce device complexity, then the ability to compensate for temperature effects is reduced, but adding compensation mechanisms increases manufacturing complexity

Engineering Contradiction:
Improvedevice complexityVSAvoidtemperature compensation capability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The compensation electrode serves multiple functions: it acts as both a structural component of the resonator and a temperature compensation mechanism. This multi-functionality allows the resonator to maintain both simplicity in structure and effectiveness in temperature compensation, avoiding the need for separate dedicated compensation components that would increase manufacturing complexity

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 approach provides flexible design parameters by accurately controlling the temperature coefficient of frequency, enhancing the resonator's performance and stability across a wide temperature range.

Implementation Method 1

a piezoelectric acoustic resonator

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

a compensation electrode configured to compensate for a resonant frequency of the piezoelectric acoustic resonator

Methodology Applied
Scientific EffectConverse piezoelectric effect: Converse Piezoelectric Effect

Data Source

PatentEP2892153B1Piezoelectric acoustic resonator with adjustable temperature compensation capability
Publication Date: 2020.08.05 ZTE CORP
  • EP2892153B1 patent drawingFigure 1
  • EP2892153B1 patent drawingFigure 2~3
  • EP2892153B1 patent drawingFigure 4

AI summary

A piezoelectric acoustic resonator with an adjustable temperature compensation capability is disclosed. The piezoelectric acoustic resonator includes: a piezoelectric acoustic reflection structure, a first electrode, a second electrode, a piezoelectric layer between the first electrode and the second electrode, and a temperature compensation layer; wherein the temperature compensation layer is a single-layer temperature compensation layer formed of SixOy material, or a composite temperature compensation layer formed by stacking material with a positive temperature coefficient of sound velocity and material with a negative temperature coefficient of sound velocity; and the temperature compensation layer is configured to: perform reverse compensation for a temperature frequency shift caused by the first electrode, the piezoelectric layer and the second electrode in the piezoelectric acoustic resonator; wherein x:y is not equal to 1:2.