GGNMOS ESD Clamp Body Contacts for Full Transistor Triggering
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Solution Overview
Problem
Existing ESD clamp devices with GGNMOS transistors often fail to trigger all transistors during an ESD event, leading to incomplete discharge of ESD current due to voltage differential issues and substrate isolation limitations, which can result in inadequate protection against electrostatic discharge.
Innovation Solution
Incorporating two types of body contact regions in GGNMOS transistors that are non-substrate isolated, allowing for hole transfer between transistors to ensure all GGNMOS transistors trigger during an ESD event, even when the source-drain voltage drops below the trigger voltage, thereby providing a reliable conductive path for ESD current discharge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If substrate isolated GGNMOS transistors are used in ESD clamp devices, then each transistor operates independently, but not all transistors trigger during an ESD event leading to incomplete discharge
Solution Approach 1:
A shared body contact region is introduced as an intermediary structure that couples multiple substrate-isolated GGNMOS transistors. This body contact region receives holes from any triggered transistor and distributes them to other transistors, enabling cross-triggering without compromising substrate isolation. The mediator allows information (holes) to pass between isolated transistors, ensuring all transistors trigger during an ESD event.
Solution Approach 2:
The body contact structure is segmented into two distinct types: substrate-isolated body contacts connected to source regions, and a shared non-substrate-isolated body contact region that couples multiple transistors. This segmentation allows each transistor to maintain its substrate isolation for independent operation while the shared body contact region enables inter-transistor hole transfer for reliable triggering.
2Reliability
If all GGNMOS transistors are triggered during an ESD event, then complete ESD current discharge is achieved, but voltage differentials must be maintained across all transistors
Solution Approach 1:
The shared body contact region acts as a mediator that equalizes voltage potentials across multiple transistors. By providing a common electrical path for holes to flow between transistors, it ensures that voltage differentials are maintained across all devices during an ESD event, enabling complete triggering without exposing individual transistors to excessive stress.
3Ease of operation
If source-drain voltage drops below trigger voltage, then normal operation is maintained, but ESD transistors may not trigger during ESD events
Solution Approach 1:
The shared body contact region serves as a mediator that enables hole transfer between transistors even when source-drain voltage is below the normal trigger threshold. During an ESD event, one transistor can trigger and transfer holes through the body contact region to other transistors, ensuring they all trigger reliably even when voltage conditions are marginal.
Solution Approach 2:
The body contact regions are pre-configured to provide a low-impedance path for hole transfer between transistors. This preliminary preparation ensures that when an ESD event occurs, holes can rapidly transfer to trigger all transistors simultaneously, without waiting for voltage to build up to trigger each transistor independently.
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
This configuration ensures that all GGNMOS transistors in the clamp device are triggered during an ESD event, effectively discharging built-up ESD charge and providing reliable protection by maintaining conductivity even when the source-drain voltage is below the trigger level.
Implementation Method 1
A body contact region of one type is electrically coupled to the source region of its transistor and a body contact region of the other type is electrically connected to at least one other body contact region of the same type of another GGNMOS transistor
Data Source
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AI summary
An electrostatic discharge circuit includes two or more GGNMOS transistors where each transistor includes two types of body contact regions. Body contact regions of one type are non substrate isolated from body contact regions of the other type. A body contact region of one type is electrically coupled to the source region of its transistor and a body contact region of the other type is electrically connected to at least one other body contact region of the same type of another GGNMOS transistor.