MOS Transistor Stress Sensor Layout for Gradient Compensation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Transistor-based stress sensors face inaccuracies due to time-varying gradient effects, such as thermal and layout gradients, which complicate the determination of mechanical stress components on semiconductor substrates, leading to unpredictable changes in electronic characteristics and performance degradation.
Innovation Solution
A transistor-based stress sensor with a specific arrangement of MOS transistors on the semiconductor substrate, where transistors are aligned in opposite current flow directions to compensate for gradients, providing a gradient-compensated output signal that isolates mechanical stress components from unwanted gradient effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If transistors are arranged in opposite current flow directions to compensate for gradients, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The stress sensor is segmented into multiple transistor units (first transistor arrangement and second transistor arrangement) with opposite current flow directions. Each arrangement measures stress components, and by segmenting the measurement function across multiple oriented transistors, the patent achieves gradient compensation while maintaining manageable device complexity through modular architecture.
2Reliability
If gradient compensation is implemented through transistor arrangement, then reliability is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent employs asymmetric transistor arrangements where the first and second transistor arrangements are oriented in opposite directions (e.g., 0° and 90°, or other complementary angles). This asymmetric orientation is deliberately designed to compensate for gradient effects, as the opposite orientations cause gradient-induced errors to cancel out while the asymmetric structure itself is optimized for manufacturing feasibility.
3Measurement precision
If multiple transistor arrangements are used for gradient compensation, then measurement precision is improved, but ease of manufacture decreases
Solution Approach 1:
The patent applies local quality by assigning specific functional roles to different transistor arrangements based on their orientations. Each transistor arrangement is optimized for its specific measurement direction, with local structural variations (such as different channel orientations) that are tailored to compensate for gradients in specific directions, rather than requiring uniform complex structures throughout the entire device.
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 enables accurate, gradient-free determination of mechanical stress components, improving the reliability and stability of semiconductor device performance by mitigating the impact of gradient-induced distortions on output signals.
Implementation Method 1
Due to various piezo effects in the semiconductor material, such as the piezo-resistive effect, piezo-MOS effect, piezo-junction effect, piezo-Hall effect and piezo-tunnel effect, important electrical and electronic parameters of the integrated circuit assembly are also influenced by the action of mechanical stress on the integrated circuit assembly.
Data Source
AI summary
A stress sensor includes a semiconductor substrate with a first transistor arrangement and a second transistor arrangement. The first transistor arrangement includes a first transistor with a first source-drain channel region and a second transistor with a second source-drain channel region. The first transistor and the second transistor are aligned relative to each other such that the current flow directions in the first and the second source-drain channel regions are opposite to each other. The second transistor arrangement includes a third transistor with a third source-drain channel region and a fourth transistor with a fourth source-drain channel region. The third transistor and the fourth transistor are aligned relative to each other such that the current flow directions in the third and the fourth source-drain channel regions are opposite to each other. The stress sensor generates a gradient-compensated output signal used to determine a mechanical stress acting on the semiconductor substrate.