Hybrid Ultrasonic Transducer Structure with PMUT–CMUT Isolation
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Solution Overview
Problem
CMUTs and PMUTs integrated in the same chip structure interfere with each other, leading to noise and performance degradation due to cross-talk and vibrations.
Innovation Solution
An integrated chip structure with PMUTs and CMUTs separated by one or more isolation chambers within a dielectric stack, which dampen cross-talk and reduce noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If CMUTs and PMUTs are integrated in the same chip structure, then device functionality and versatility are improved, but cross-talk and vibrations cause noise and performance degradation
Solution Approach 1:
The chip structure is segmented into distinct regions with isolation chambers positioned between CMUT and PMUT arrays. These chambers physically divide the integrated structure into separate functional zones, preventing direct mechanical coupling and reducing cross-talk between the two transducer types while maintaining their integrated functionality.
Solution Approach 2:
Isolation chambers act as intermediary elements between CMUT and PMUT arrays. These chambers serve as mechanical buffers that decouple the two transducer types, absorbing and dampening vibrations to prevent harmful cross-talk while allowing both transducer types to coexist in the same chip structure.
2Measurement precision
If isolation chambers are added to separate CMUTs and PMUTs, then noise reduction and signal-to-noise ratio are improved, but device complexity increases
Solution Approach 1:
The isolation chambers divide the chip into distinct functional segments, creating clear separation zones between CMUT and PMUT arrays. This segmentation approach achieves noise reduction through systematic spatial organization rather than complex isolation mechanisms, simplifying the overall design while improving signal quality.
Solution Approach 2:
The harmful vibrational energy is extracted and contained within the isolation chambers, removing it from the main signal paths. By extracting the noise-generating vibrations into dedicated isolation zones, the system achieves high signal-to-noise ratio without requiring complex active noise cancellation or sophisticated structural designs.
3Reliability
If isolation chambers are used to reduce cross-talk, then performance is improved, but manufacturing complexity increases
Solution Approach 1:
The manufacturing process is segmented into standardized stages: forming isolation chambers first, then positioning and integrating CMUT and PMUT arrays separately into the predefined zones. This segmentation allows each component to be manufactured and tested independently before final integration, simplifying the overall manufacturing process despite the added structural complexity.
Solution Approach 2:
Isolation chambers are formed and positioned in advance during the substrate preparation stage, before the sensitive CMUT and PMUT arrays are integrated. This preliminary action establishes the mechanical isolation framework early in the manufacturing process, making subsequent array integration simpler and reducing the risk of damage to the delicate transducer elements.
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 isolation chambers improve the performance of the integrated chip structure by reducing noise and enhancing the signal-to-noise ratio.
Implementation Method 1
An integrated chip structure with PMUTs and CMUTs separated by one or more isolation chambers within a dielectric stack, which dampen cross-talk and reduce noise.
Data Source
AI summary
The present disclosure relates to an integrated chip structure. The integrated chip structure includes a dielectric stack disposed on a substrate. The integrated chip structure further includes one or more piezoelectric ultrasonic transducers (PMUTs) and one or more capacitive ultrasonic transducers (CMUTs). The one or more PMUTs include a piezoelectric stack disposed within the dielectric stack over one or more PMUT cavities. The one or more CMUTs include electrodes disposed within the dielectric stack and separated by one or more CMUT cavities. An isolation chamber is arranged within the dielectric stack laterally between the one or more PMUTs and the one or more CMUTs. The isolation chamber vertically extends past at least a part of both the one or more PMUTs and the one or more CMUTs.