Multi-Channel TVS Structure With Isolation Trenches for Low Capacitance
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Solution Overview
Problem
Conventional transient voltage suppressors face challenges in reducing equivalent capacitances on current dissipation paths, leading to increased circuit area, serial resistance, and costs as the number of channels increases, due to the need for additional diodes in series.
Innovation Solution
A multi-channel transient voltage suppression device is designed with a semiconductor substrate, semiconductor layer, and bidirectional transient voltage suppression structures, including isolation trenches to reduce parasitic capacitances without additional components in series, utilizing a single bidirectional structure to achieve low-capacitance, reduced layout area, and lower costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If additional diodes are arranged in series on each channel to reduce equivalent capacitances, then the equivalent capacitance on current dissipation paths is reduced, but the circuit area, serial resistance, and cost increase significantly
Solution Approach 1:
The patent merges multiple diode functions into a single bidirectional transient voltage suppression structure. Instead of using separate diodes for each polarity protection, a single bidirectional structure handles both positive and negative voltage suppression, thereby reducing the number of components and circuit area while maintaining ESD protection capability.
Solution Approach 2:
The bidirectional transient voltage suppression structure serves multiple functions: it provides voltage suppression for both positive and negative polarities, acts as an ESD protection device, and eliminates the need for additional series diodes. This multi-functionality reduces component count and circuit complexity while achieving the same protective effect.
2Reliability
If additional diodes are arranged in series on each channel to reduce equivalent capacitances, then the equivalent capacitance on current dissipation paths is reduced, but the serial resistance increases
Solution Approach 1:
The patent combines the functions of multiple series diodes into a single bidirectional transient voltage suppression structure. This merging eliminates the cumulative series resistance that would result from stacking multiple diodes in series, while still achieving effective voltage suppression and ESD protection through the bidirectional structure's inherent design.
3Reliability
If additional diodes are arranged in series on each channel to reduce equivalent capacitances, then the equivalent capacitance on current dissipation paths is reduced, but the cost increases dramatically
Solution Approach 1:
The patent merges multiple discrete diode components into a single integrated bidirectional transient voltage suppression structure. This consolidation reduces the total number of components that need to be sourced, placed, and tested, thereby dramatically reducing manufacturing costs while maintaining the same level of ESD protection.
Solution Approach 2:
The bidirectional structure provides multiple protection functions in a single component, eliminating the need for multiple separate diodes. This multi-functionality reduces bill of materials costs, assembly costs, and testing costs, making the ESD protection solution more cost-effective.
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 effectively reduces parasitic capacitances, layout area, serial resistance, and costs while maintaining effective ESD protection by isolating the semiconductor layer and shallower substrate layer, thereby improving the efficiency and cost-effectiveness of the transient voltage suppression device.
Implementation Method 1
the isolation trench has a height larger than the height of the semiconductor layer and surrounds the bidirectional transient voltage suppression structures
Data Source
AI summary
A multi-channel transient voltage suppression device includes a semiconductor substrate, a semiconductor layer, at least two bidirectional transient voltage suppression structures, and at least one isolation trench. The semiconductor substrate, having a first conductivity type, is coupled to a grounding terminal. The semiconductor layer, having a second conductivity type opposite to the first conductivity type, is formed on the semiconductor substrate. The bidirectional transient voltage suppression structures are formed in the semiconductor layer. Each bidirectional transient voltage suppression structure is coupled to an input/output (I/O) pin and the grounding terminal. The isolation trench is formed in the semiconductor substrate and the semiconductor layer and formed between the bidirectional transient voltage suppression structures. The isolation trench has a height larger than the height of the semiconductor layer and surrounds the bidirectional transient voltage suppression structures.