Bipolar Transistor MEMS Pressure Sensor Temperature Drift
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Solution Overview
Problem
Traditional MEMS piezoresistive pressure sensors face challenges in balancing sensitivity, measurement range, and linearity, with temperature drift issues limiting their application in high-end fields, and existing compensation methods increase sensor size and power consumption.
Innovation Solution
A bipolar transistor type MEMS pressure sensor is developed, featuring a thin film suspended on a substrate with a bipolar transistor that includes a base region, collector region, and emitter region, which senses deformation through resistance changes, and is designed to maintain sensitivity without altering the thin film's size, while also compensating for temperature drift by functioning as both a pressure-sensitive resistor and a component of the bipolar transistor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the ratio of the area to thickness of the pressure-sensitive thin film is increased to improve sensitivity, then sensitivity is improved, but the measurement range decreases and linearity deteriorates
Solution Approach 1:
The patent changes the functional parameter of the sensing element by integrating a bipolar transistor structure with the thin film, transforming it from a simple piezoresistive element to an active transistor-based sensor. This allows sensitivity enhancement through transistor amplification rather than geometric modification, resolving the contradiction between sensitivity and measurement range
Solution Approach 2:
The patent creates a composite structure combining the thin film with bipolar transistor components (base region, collector region, emitter region). This composite design enables the system to achieve high sensitivity through the transistor effect while maintaining the original thin film geometry, thus preserving measurement range and linearity
2Measurement precision
If the ratio of the area to thickness of the pressure-sensitive thin film is increased to improve sensitivity, then sensitivity is improved, but linearity deteriorates
Solution Approach 1:
The patent changes the operational parameter from passive piezoresistive response to active transistor amplification, where the bipolar transistor's current amplification characteristic provides a more linear relationship between input pressure and output signal, maintaining linearity while achieving high sensitivity
3Reliability
If subsequent circuit compensation methods are used to compensate for temperature drift, then temperature drift is compensated, but the overall size and power consumption of the sensor increases
Solution Approach 1:
The patent merges the temperature compensation function with the pressure sensing function by integrating the bipolar transistor directly into the thin film structure. The transistor serves dual purposes: pressure detection and temperature compensation, eliminating the need for separate compensation circuits and reducing overall device size
Solution Approach 2:
The bipolar transistor structure performs multiple functions simultaneously: it acts as the pressure-sensitive element, provides signal amplification, and enables temperature compensation through its inherent electrical characteristics. This multi-functionality reduces the need for additional components, thereby reducing sensor size and power consumption
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 solution enhances sensitivity without affecting the measurement range or linearity and effectively suppresses temperature drift by leveraging the bipolar transistor's amplification effect and resistance changes, improving the sensor's integration and simplifying the preparation process.
Implementation Method 1
the base region is disposed on the thin film and is configured to sense deformation of the thin film through a change in resistance value
Implementation Method 2
the bipolar transistor's amplification effect and resistance changes
Data Source
AI summary
The present disclosure discloses a bipolar transistor type MEMS pressure sensor and a preparation method thereof. The bipolar transistor type MEMS pressure sensor includes a thin film, a cantilever beam and a bipolar transistor. The bipolar transistor includes a base region, a collector region and an emitter region. The base region is configured to sense deformation of the thin film through a change in resistance value. For the bipolar transistor type MEMS pressure sensor of the disclosure, sensitivity of the sensor can be effectively improved without changing the performance indicators such as the measurement range and nonlinearity. Meanwhile, the bipolar transistor is used as a pressure-sensitive element, so that temperature drift of the sensor can be effectively inhibited.