Bipolar Transistor Stress Sensor with Hall Effect Interference Cancellation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Semiconductor devices face challenges in accurately measuring mechanical stress due to packaging, which can be influenced by magnetic fields, and existing stress sensors are not effective in distinguishing stress direction or magnitude, leading to errors in stress measurement.
Innovation Solution
A semiconductor-based stress sensor system that utilizes a Hall plate or bipolar transistor device with multiple collector terminals to measure mechanical stress while mitigating the effects of magnetic fields, characterizing stress direction and magnitude, and using this information to counteract stress influences on circuit elements through error correction and calibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a Hall sensor is used to measure mechanical stress, then stress measurement capability is provided, but magnetic field interference corrupts the stress measurement accuracy
Solution Approach 1:
The patent measures the Hall effect voltage generated by magnetic fields and uses this measurement to calculate and remove the magnetic field's contribution to the stress measurement. By quantifying the harmful magnetic field effect through the Hall sensor itself, the system converts the interference into useful correction data that improves measurement accuracy.
Solution Approach 2:
The system continuously monitors the Hall effect voltage and feeds this information back into the stress calculation algorithm. The measured Hall voltage is used to dynamically adjust and correct the stress measurement in real-time, creating a closed-loop system that compensates for magnetic field interference.
2Measurement precision
If existing stress sensors are used, then stress detection is provided, but the sensors cannot distinguish stress direction or magnitude, leading to measurement errors
Solution Approach 1:
The patent uses multiple piezoresistive elements arranged in specific orientations (e.g., orthogonal directions) to segment the stress measurement task. Each element measures stress along its specific axis, and by combining these segmented measurements, the system reconstructs the complete stress state including direction and magnitude.
Solution Approach 2:
The system transitions from scalar stress measurement to vector stress measurement by incorporating directional information through multiple sensing elements. The measurements are extended from a single magnitude value to include directional components, effectively adding dimensional information to the stress characterization.
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 system provides accurate stress measurement by canceling magnetic field interference and offering stress compensation, enhancing the reliability of semiconductor device performance by accurately determining stress direction and magnitude.
Implementation Method 1
The Hall effect refers to a voltage difference that can be generated across an electric conductor in the presence of a magnetic field. A direction of the generated voltage can be transverse to an electric current in the conductor and to the magnetic field perpendicular to the current.
Implementation Method 2
The first and second electric signals can indicate a charge carrier mobility characteristic of the semiconductor, which can be used to provide an indication of physical stress on the sensor.
Implementation Method 3
The physical stress indicator can be based on a current deflection characteristic of a base region of the transistor device.
Data Source
AI summary
A semiconductor-based stress sensor can include a bipolar transistor device with first and second collector terminals. An excitation circuit can provide an excitation signal to an emitter terminal of the bipolar transistor device, and a physical stress indicator for the semiconductor can be provided based on a relationship between signals measured at the collector terminals in response to the excitation signal. The signals can indicate a charge carrier mobility characteristic of the semiconductor, which can be used to provide an indication of physical stress. In an example, the physical stress indicator is based on a current deflection characteristic of a base region of the transistor device.