Gate-Coupled NMOS ESD Protection Trigger Voltage Reduction
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Solution Overview
Problem
Modern semiconductor chips are vulnerable to electrostatic discharge (ESD) due to external electrostatic charges, which can damage internal circuits, and existing ESD protection devices have high trigger voltages, leading to delayed protection and potential damage during ESD events.
Innovation Solution
A semiconductor ESD protection device with a substrate trigger mechanism, featuring a gate-coupling NMOS (GCNMOS) structure where the body region is electrically connected to the gate, reducing the trigger voltage by increasing the base voltage of a parasitic bipolar junction transistor, thus enabling quicker activation and lower turn-on voltage compared to conventional devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional ESD protection devices are used, then the device structure is simple and easy to manufacture, but the trigger voltage is high causing delayed protection
Solution Approach 1:
The ESD protection device is divided into distinct functional regions: a first conductivity type substrate, a second conductivity type body region, source/drain regions, and a gate. This segmentation allows independent optimization of each region's properties to achieve lower trigger voltage while maintaining manufacturing simplicity.
Solution Approach 2:
Different regions of the device are assigned different conductivity types and doping concentrations tailored to their specific functions. The body region has higher doping concentration than the substrate, and the source/drain regions have optimized doping profiles, creating local quality variations that reduce trigger voltage without complicating the overall device structure.
2Speed
If the trigger voltage is reduced to enable faster protection, then the turn-on speed improves, but the device requires more complex structure with body region connection
Solution Approach 1:
The gate is electrically connected to the body region, merging two functional elements into a coupled structure. This gate-body connection creates a feedback mechanism that accelerates turn-on speed by allowing the gate voltage to directly influence the body region potential, enabling faster ESD protection response.
Solution Approach 2:
The doping concentration of the body region is increased relative to the substrate, and the gate-body connection modifies the electrical parameters dynamically during ESD events. These parameter changes reduce the trigger voltage threshold and improve turn-on speed while maintaining a relatively simple device structure that can be integrated into existing semiconductor processes.
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 reduces the trigger voltage to less than half of conventional devices, enhancing the turn-on speed and preventing damage from ESD events while being integratable into existing semiconductor manufacturing processes without increased complexity or cost.
Implementation Method 1
a gate-coupling NMOS (GCNMOS) structure where the body region is electrically connected to the gate
Implementation Method 2
reducing the trigger voltage by increasing the base voltage of a parasitic bipolar junction transistor
Data Source
AI summary
The present disclosure provides a semiconductor ESD protection device. The semiconductor ESD protection device includes a substrate including a first conductivity type, a gate formed on the substrate, a source region and a drain region formed in the substrate, and a body region formed in the substrate. The substrate and the body region include a first conductivity type. The source region and the drain region include a second conductivity type. And the first conductivity type and the second conductivity type are complementary to each other. The body region is electrically connected to the gate.