MOSFET Guard Ring Layout for Distributed ESD Protection
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Solution Overview
Problem
Conventional semiconductor devices face challenges in effectively protecting internal circuits from electrostatic discharge (ESD) currents, which can lead to damage by concentrating ESD currents on specific transistors, resulting in inefficient protection and potential device failure.
Innovation Solution
The semiconductor device incorporates a configuration of MOSFET-based switching elements and protection elements arranged in specific well regions and guard rings, where the driver switching elements and protection switching elements are connected in parallel, with the driver switching element located at the center and protection elements surrounding it, to distribute ESD currents and prevent concentration on individual transistors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional protection circuits are used, then ESD protection is provided, but ESD currents concentrate on specific transistors causing potential device failure
Solution Approach 1:
The protection circuit is divided into multiple parallel protection switching elements (first protection switching element and second protection switching element) instead of using a single transistor. This segmentation distributes the ESD current across multiple paths, preventing current concentration on individual transistors and improving overall protection effectiveness.
Solution Approach 2:
A dedicated protection switching element is introduced as an intermediary component between the internal circuit and the external environment. This protection switching element is specifically designed to handle ESD events, acting as a mediator that absorbs and dissipates ESD energy before it can reach and damage the internal circuit transistors.
2Reliability
If protection switching elements are added, then ESD protection is improved, but device complexity increases
Solution Approach 1:
The protection switching elements are merged with the existing driver switching element structure, sharing common terminals and well regions. The first and second protection switching elements are integrated alongside the driver switching element, utilizing the same power supply terminal and output terminal, thereby reducing the need for additional separate components and simplifying the overall device structure.
Solution Approach 2:
The protection switching elements are designed to serve multiple functions: they provide ESD protection during normal operation and can also function as part of the driver circuit when activated. This multi-functionality reduces the need for dedicated separate protection components, thereby reducing device complexity while maintaining effective ESD protection.
Data Source
AI summary
A semiconductor device includes: first switching elements arranged in a first direction and each including a first gate wire extending in a second direction; and a back gate guard ring surrounding the first switching elements. The first switching elements are connected to each other in parallel and connected between a first pad and a second pad. The first switching elements include a driver switching element, the driver switching element being at least one first switching element located between two first end switching elements located at opposite ends of the first switching elements in the first direction. The first switching elements excluding the driver switching element include a first protection switching element, the first gate wire of the first protection switching element being connected to the first pad or the second pad.