Semiconductor Protection Device Trigger Voltage Control
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Solution Overview
Problem
Existing semiconductor protection devices face challenges in independently controlling trigger voltage without affecting hold voltage, which is crucial for protecting internal circuits against electrostatic discharge and abnormal voltages.
Innovation Solution
The semiconductor device incorporates a specific structure with multiple conductivity type regions, including a second conductivity type layer with higher impurity concentration, strategically positioned to control trigger voltage by adjusting the distance between layers, while maintaining hold voltage stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the base width of the horizontal bipolar transistor is reduced to lower the trigger voltage, then the current amplification factor increases, but the hold voltage decreases
Solution Approach 1:
The base region is divided into two separate doped regions (second and fourth semiconductor regions) instead of a single continuous base. This segmentation allows independent control of trigger voltage (via distance between regions) and hold voltage (via base width maintenance), resolving the contradiction between lowering trigger voltage and maintaining hold voltage stability.
Solution Approach 2:
A sixth semiconductor region of first conductivity type is introduced as an intermediary region that contains the fourth semiconductor region and is electrically short-circuited with the fifth semiconductor region. This intermediary structure maintains the base width for stable hold voltage while allowing the trigger voltage to be controlled by the distance between the second and fourth regions.
2Adaptability or versatility
If the trigger voltage is lowered to match lower withstand voltage of protected devices, then the protection threshold is reduced, but the hold voltage decreases which affects protection effectiveness
Solution Approach 1:
By segmenting the base into separate doped regions, the patent enables independent adjustment of trigger voltage to match different protected device withstand voltages without compromising hold voltage, thus maintaining protection effectiveness across different application requirements.
Solution Approach 2:
The patent changes the structural parameters by introducing separate doped regions with specific impurity concentrations and distances, allowing trigger voltage to be adjusted as an independent parameter while maintaining hold voltage within the required range for effective protection.
Data Source
AI summary
A semiconductor device including a protection device and a protected device, the protection device includes a first semiconductor region of a second conductivity type formed over a substrate, a second semiconductor region of the second conductivity type provided in the first semiconductor region, having a higher impurity concentration than the first semiconductor region, a third semiconductor region of the second conductivity type formed in a surface layer of the second semiconductor region, having a higher impurity concentration than the second semiconductor region, a fourth semiconductor region of the second conductivity type formed in the first semiconductor region and located away from the third semiconductor region, having a higher impurity concentration than the first semiconductor region, a fifth semiconductor region of a first conductivity type formed in the first semiconductor region and electrically short-circuited with the fourth semiconductor region, and a sixth semiconductor region of the first conductivity type.