Piezoelectric Pressure Sensor Semiconductor Charge Transfer
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Solution Overview
Problem
Current piezoelectric pressure sensors have low sensitivity, making it difficult to measure small voltage variations and low pressures, which limits their ability to detect low pressure variations effectively.
Innovation Solution
A pressure sensor design featuring a piezoelectric material with a semiconductor layer and electrodes, where the piezoelectric layer is in contact with the semiconductor and electrodes, allowing for the transfer of electric charges created by pressure into a semiconductor, enabling current measurement that is more reliable than voltage measurement, and incorporating a dielectric layer and aligned dipoles to enhance sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If piezoelectric pressure sensors measure voltage across piezoelectric material, then pressure can be detected, but measurement sensitivity is low due to difficulty in measuring small voltage variations
Solution Approach 1:
The patent replaces the conventional voltage measurement approach with a current measurement approach using a semiconductor layer. The piezoelectric material generates charges under pressure, which are transferred to the semiconductor layer, producing a measurable current signal that is much more sensitive and easier to detect than the small voltage variations in traditional sensors.
Solution Approach 2:
The semiconductor layer acts as an intermediary between the piezoelectric material and the measurement system. It receives charges from the piezoelectric material under pressure and converts them into a measurable current signal, amplifying the detection capability and solving the problem of measuring small voltage variations.
2Measurement precision
If piezoelectric material is used for pressure sensing, then pressure detection is enabled, but sensitivity remains low limiting detection of low pressures
Solution Approach 1:
The patent substitutes the voltage measurement system with a current measurement system based on semiconductor properties. This replacement dramatically improves sensitivity, enabling reliable detection of low pressures and small pressure variations that were previously undetectable with conventional piezoelectric sensors.
Solution Approach 2:
The patent changes the measurement parameter from voltage to current by introducing a semiconductor layer. This parameter change enhances the sensitivity of the sensor, allowing it to detect very small pressure variations and low pressures with high reliability.
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 sensor achieves high measurement sensitivity by transferring pressure-induced charges into a semiconductor, allowing for more accurate detection of pressures, with aligned dipoles increasing charge collection and sensor sensitivity, and a 'high-gate' field-effect transistor structure enabling both transistor and pressure sensor functionality.
Implementation Method 1
piezoelectric material, such as quartz, for example, electrically charges when said material is submitted to mechanical strain such as a pressure
Implementation Method 2
transfer the charges, created when a pressure is exerted on the piezoelectric layer, into a semiconductor which is in electric contact therewith
Implementation Method 3
the piezoelectric layer comprises dipoles aligned along the direction of the exerted pressure, which enables to increase the number of collected charges, and thus to increase the sensor sensitivity
Data Source
AI summary
A pressure sensor including a lower substrate having two electrodes partially covered with a semiconductor layer and a piezoelectric layer made of a piezoelectric material, and in contact with the semiconductor layer in such a way that semiconductor material is in contact with the piezoelectric material and with the two electrodes, deposited thereon. The electrodes are intended to be connected to a voltage source or to a device for measuring the intensity of a current generated by the displacement of the electric charges in the semiconductor layer between the electrodes, said electric charges being created when a pressure is exerted on the piezoelectric layer.