Movable Piezo Element Using AlN for Low-Voltage In-Plane Oscillation
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Solution Overview
Problem
Existing piezoelectric systems, particularly those using lead zirconate titanate (PZT), are costly, power-intensive, and non-compliant with RoHS regulations due to high permittivity and toxicity, and struggle with in-plane oscillations and compatibility with nano-electromechanical systems, while electrostatic systems require high voltages and are not compatible with external oscillations.
Innovation Solution
A movable piezo element with a substrate structure featuring an intermediate layer, a first electrode layer of conductive non-ferroelectric material, and a ferroelectric, piezoelectric, or flexoelectric layer, where the oscillation direction is controlled by selective coverage of the layer stack on the bar, allowing for low voltage operation and integration with existing processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If lead zirconate titanate (PZT) is used for piezoelectric oscillation, then good integration capability is achieved, but cost increases and power consumption increases due to high permittivity and toxicity
Solution Approach 1:
The patent changes the material parameters by using aluminum nitride (AlN) instead of PZT, which has lower permittivity and enables low-voltage operation. This parameter change resolves the contradiction by maintaining integration capability while reducing power consumption and eliminating toxicity concerns.
Solution Approach 2:
The patent employs standard semiconductor manufacturing processes and commercially available AlN materials, replacing expensive PZT with a cheaper, non-toxic alternative that can be produced through established industrial processes, thereby reducing cost and power consumption.
2Adaptability or versatility
If PZT is used for piezoelectric oscillation, then good integration capability is achieved, but manufacturing complexity increases due to high crystallization temperatures and material compatibility issues
Solution Approach 1:
The patent changes the material system from high-temperature PZT to low-temperature AlN, enabling compatibility with standard semiconductor processes. This parameter change eliminates the need for high crystallization temperatures and resolves manufacturing complexity issues while maintaining integration capability.
Solution Approach 2:
The patent replaces the mechanical sintering and high-temperature crystallization processes required for PZT with vapor-phase deposition processes suitable for AlN, substituting complex high-temperature manufacturing with simpler, lower-temperature processes compatible with existing semiconductor fabrication.
3Shape
If electrostatic comb drives are used for oscillation, then out-of-plane oscillation is achieved, but high electrical voltages are required to ensure large excursion range
Solution Approach 1:
The patent replaces electrostatic actuation with piezoelectric actuation using AlN. This substitution enables the same out-of-plane oscillation functionality to be achieved with much lower voltages, as piezoelectric materials directly convert low-voltage electrical signals into mechanical displacement without requiring high electric fields.
4Adaptability or versatility
If PZT is used for piezoelectric oscillation, then good integration capability is achieved, but reliability decreases due to toxicity and RoHS non-compliance
Solution Approach 1:
The patent replaces toxic PZT with non-toxic AlN, which is RoHS compliant and environmentally friendly. This substitution maintains integration capability while improving reliability by eliminating hazardous substances, ensuring compliance with environmental regulations.
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
Enables reliable, low-power, and cost-effective piezoelectric elements capable of in-plane and out-of-plane oscillations, compatible with nano-electromechanical systems, with reduced material toxicity and compliance with RoHS regulations, suitable for various microelectromechanical applications.
Implementation Method 1
A movable piezo element, that is a movable or moving piezoelectric element, preferably a piezo actuator
Implementation Method 2
A ferroelectric, piezoelectric, and/or flexoelectric layer is/are arranged on the first electrode layer
Implementation Method 3
A ferroelectric, piezoelectric, and/or flexoelectric layer is/are arranged on the first electrode layer
Implementation Method 4
The second substrate layer is structured such that at least one bar of the second layer mounted on one side is formed
Implementation Method 5
The oscillation direction can be directly specified by selection of the sides to be covered, with a side surface typically being intended to designate every surface angled with respect to a surface facing or remote from the substrate
Data Source
AI summary
A movable piezo element and to a method for producing the element are provided. The movable piezo element may have a structured substrate, in which an intermediate layer is arranged between a first substrate layer and a second substrate layer. The element may also have a first electrode layer. The element may also have a second electrode layer arranged on the ferroelectric, piezoelectric, or flexoelectric layer. The second substrate layer may be structured such that at least one bar of the second substrate layer is formed. The bar may be clamped on one side and may be physically spaced from the first substrate layer. A surface of the bar facing away from the first substrate layer, and/or a lateral surface of the bar, may be at least partly covered by another layer.