Stacked ESD Detection Elements for High-Voltage Protection
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Solution Overview
Problem
Conventional ESD protection devices face challenges when interfacing between lower-voltage and higher-voltage circuits, as they may not reliably withstand high-voltage signals, leading to potential damage from ESD pulses, and using different gate oxide thicknesses complicates manufacturing and delays response times.
Innovation Solution
The implementation of 'stacked' ESD detection elements in series within ESD protection devices allows for the use of a single gate oxide thickness, enabling reliable protection across different voltage levels by effectively stepping down voltage levels across individual semiconductor devices, ensuring uniform response times and streamlined manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a thicker gate oxide is used for ESD protection devices to withstand higher voltages, then voltage withstand capability is improved, but trigger voltage increases and response time slows down
Solution Approach 1:
The ESD protection device is divided into multiple stacked ESD detection elements connected in series between the first and second circuit nodes. Each detection element experiences only a portion of the total voltage, allowing the use of thinner gate oxides that provide faster response times while still withstanding the overall high voltage through the series combination.
Solution Approach 2:
The patent changes the structural parameter of the gate oxide from thick to thin, fundamentally altering the device characteristics. Thin gate oxides enable lower trigger voltages and faster response times, while the series stacking architecture compensates for the reduced individual voltage tolerance, achieving both speed and voltage handling capability.
2Adaptability or versatility
If two different gate oxide thicknesses are used to interface with different voltage circuits, then voltage compatibility is improved, but manufacturing complexity increases
Solution Approach 1:
The stacked ESD detection element structure serves as a universal solution that can interface with circuits operating at different voltage levels. By adjusting the number of stacked elements rather than changing gate oxide thicknesses, a single device architecture can adapt to various voltage requirements, eliminating the need for multiple device types and simplifying manufacturing.
Solution Approach 2:
Instead of changing the gate oxide thickness parameter to achieve voltage compatibility, the patent changes the number of stacked detection elements. This parameter change allows the same device structure with uniform gate oxide thickness to be adapted for different voltage levels, maintaining manufacturing simplicity while achieving voltage compatibility.
3Ease of manufacture
If lower-voltage devices are used for high-voltage circuits, then manufacturing is simplified, but the devices cannot reliably withstand high-voltage signals
Solution Approach 1:
The high-voltage ESD protection function is segmented across multiple lower-voltage detection elements connected in series. Each element operates within its safe voltage range while the series combination collectively withstands the full high-voltage stress, enabling the use of simpler lower-voltage devices for high-voltage applications without compromising reliability.
Solution Approach 2:
The patent changes the operational parameter by distributing voltage across multiple series-connected devices rather than requiring individual devices to withstand the full voltage. This allows lower-voltage devices with simpler manufacturing to be used in high-voltage applications, achieving both manufacturing ease and reliable voltage tolerance through the series architecture.
Data Source
AI summary
Some embodiments relate to an electrostatic discharge (ESD) protection device to protect a circuit that is electrically connected to first and second circuit nodes from an ESD event. The ESD protection device includes a first electrical path extending between the first and second circuit nodes and including first and second ESD detection elements arranged thereon. The ESD protection device also includes first and second voltage bias elements having respective inputs electrically connected to respective outputs of the first and second ESD detection elements. A second electrical path extends between the first and second circuit nodes and is in parallel with the first electrical path. The second electrical path includes a voltage controlled shunt network having at least two control terminals electrically connected to respective outputs of the first and second voltage bias elements. Other embodiments are also disclosed.