Bidirectional Zener Diode Capacitance Tuning via Segmented Diffusion
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Solution Overview
Problem
Existing bidirectional Zener diodes require significant design changes to achieve desired capacitance between terminals, as capacitance is heavily dependent on the shape and size of the diffusion region, making it difficult to easily achieve various capacitance values for different applications.
Innovation Solution
A bidirectional Zener diode configuration with multiple diffusion regions and pseudo-diode regions, where diode regions are electrically connected and pseudo-diode regions are isolated, allowing for adjustment of capacitance by varying the number and arrangement of these regions without changing the array pattern, enabling a range of capacitance values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the shape and size of the diffusion region are changed to achieve desired capacitance, then the capacitance between terminals can be adjusted, but the design complexity increases significantly
Solution Approach 1:
The diffusion region is divided into multiple discrete diffusion regions (first diffusion region, second diffusion region, third diffusion region, etc.) that can be independently controlled. Each diffusion region contributes to the total capacitance, allowing the desired capacitance value to be achieved by selectively activating or deactivating specific regions rather than changing the overall shape and size of a single diffusion region.
2Adaptability or versatility
If multiple diffusion regions are used to achieve various capacitance values, then capacitance adjustment becomes easier, but the device structure becomes more complex
Solution Approach 1:
The patent introduces a control mechanism that can dynamically select which diffusion regions are electrically connected to the terminals. By controlling the connection state of each diffusion region, the total capacitance can be adjusted without physically changing the device structure. The diffusion regions remain in place, but their electrical connectivity is dynamically controlled to achieve different capacitance values.
3Manufacturing precision
If the array pattern is changed to achieve desired capacitance, then capacitance values can be varied, but the manufacturing process becomes more complex
Solution Approach 1:
The patent designs a universal array pattern where multiple diffusion regions are arranged in a fixed geometric configuration. This same array pattern can produce different capacitance values not by changing the pattern itself, but by selectively controlling which regions are electrically active. The fixed array pattern simplifies manufacturing while the selective control mechanism provides capacitance variability.
Data Source
AI summary
A bidirectional Zener diode of the present invention includes a semiconductor substrate of a first conductivity type, a first electrode and a second electrode which are defined on the semiconductor substrate, and a plurality of diffusion regions of a second conductivity type, which are defined at intervals from one another on a surface portion of the semiconductor substrate, to define p-n junctions with the semiconductor substrate, and the plurality of diffusion regions include diode regions which are electrically connected to the first electrode and the second electrode, and pseudo-diode regions which are electrically isolated from the first electrode and the second electrode.