PMUT Isolation Trenches for Electrical Segmentation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In piezoelectric micromachined ultrasonic transducer (PMUT) arrays, adjacent devices often have shared or interconnected components, leading to limited operational flexibility and the need for additional circuitry to isolate conductive plane layers, which can result in parasitic connections and reduced signal processing capabilities.
Innovation Solution
The implementation of a dual-electrode PMUT device design with isolation trenches etched through the conductive plane layer and piezoelectric layer, along with a conductive plane layer located between the piezoelectric and structural layers, allows for independent operation of each PMUT device by electrically isolating the conductive plane layers, enabling separate control for transmit and receive modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If adjacent PMUT devices have shared or interconnected components, then manufacturing efficiency is improved, but operational flexibility is limited and parasitic connections occur
Solution Approach 1:
The patent divides the conductive plane layer into separate isolated sections for adjacent PMUT devices using etched isolation trenches. This segmentation allows each device to operate independently with its own conductive plane, eliminating parasitic connections while maintaining manufacturing efficiency through shared fabrication processes.
Solution Approach 2:
The patent applies local isolation through etched trenches only where needed between adjacent devices, while maintaining continuous conductive planes within each individual PMUT device. This localized approach provides operational flexibility where required without compromising the overall manufacturing efficiency of the array.
2Reliability
If additional circuitry is added to isolate conductive plane layers, then parasitic connections are reduced, but device complexity increases
Solution Approach 1:
The patent extracts the isolation function from additional circuitry and implements it directly through physical etched trenches in the conductive plane layer. This eliminates the need for separate isolation circuitry while effectively preventing parasitic connections, thereby reducing device complexity.
Solution Approach 2:
The etched isolation trenches serve as physical intermediaries that directly separate adjacent conductive plane layers, providing isolation without requiring additional active circuitry. This passive structural solution reduces complexity while maintaining reliability.
3Device complexity
If ground-connected configuration is used, then device simplicity is maintained, but signal loss increases and sensitivity is reduced
Solution Approach 1:
The patent segments the conductive plane layer to create isolated conductive regions for each PMUT device, preventing parasitic signal paths to ground while maintaining electrical connectivity within each device. This segmentation reduces signal loss and improves sensitivity without significantly increasing device complexity.
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 design enhances the operational flexibility and sensitivity of PMUT devices by up to 3 dB compared to ground-connected configurations, reducing signal loss and allowing for independent control of electrodes, thereby improving the overall performance of PMUT arrays.
Implementation Method 1
a piezoelectric material that provides an electro-mechanical response based on a given input signal. For example, when an electrical signal is applied to the piezoelectric material, the material may exhibit a mechanical response.
Implementation Method 2
In response to a received mechanical signal, the piezoelectric material may exhibit an electrical response.
Implementation Method 3
an isolation trench that extends through the conductive plane layer and at least one of the piezoelectric layer or the structural layer, wherein the isolation trench surrounds the conductive plane layer within the PMUT device
Data Source
AI summary
A piezoelectric micromachined ultrasonic transducer (PMUT) device includes a layer of piezoelectric material that is activated and sensed by an electrode and a conductive plane layer. The conductive plane layer may be electrically connected to processing circuitry by a via that extends through the piezoelectric layer. One or more isolation trenches extend through the conductive plane layer to isolate the conductive plane layer from other conductive plane layers of adjacent PMUT devices of a PMUT array.