Semiconductor ESD Protection Circuit With Lower Trigger Voltage
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Solution Overview
Problem
Existing semiconductor devices face challenges in effectively protecting internal semiconductor elements from electrostatic discharge (ESD) due to the difference between breakdown voltage and trigger voltage in ESD protection circuits.
Innovation Solution
The implementation of an ESD protection circuit that includes a PNP transistor, NPN transistors, and an NMOS transistor, with a diode and resistor configurations, reduces the difference between breakdown voltage and trigger voltage, providing effective protection by allowing ESD current to flow safely through the circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an ESD protection circuit is designed with conventional transistor configurations, then the breakdown voltage is maintained at an appropriate level, but the trigger voltage remains significantly higher than the breakdown voltage, reducing protection effectiveness
Solution Approach 1:
The ESD protection circuit is divided into multiple functional sections: a first ESD protection circuit section with a PNP transistor and first NPN transistor, and a second ESD protection circuit section with a second NPN transistor and NMOS transistor. This segmentation allows independent optimization of each section's characteristics, enabling the trigger voltage to be reduced closer to the breakdown voltage while maintaining overall protection effectiveness.
Solution Approach 2:
The patent employs dynamic voltage control through the gate structure of the NMOS transistor, which is connected to receive a control signal. This dynamic adjustment capability allows the circuit to adaptively optimize the trigger voltage based on operating conditions, reducing the gap between breakdown voltage and trigger voltage for improved protection response.
2Object-affected harmful factors
If the trigger voltage is reduced to be closer to the breakdown voltage for better protection, then ESD current can flow more easily through the protection circuit, but the circuit may become less selective in allowing only necessary current paths
Solution Approach 1:
The multi-transistor configuration creates inherent feedback mechanisms where the activation of one transistor influences the others. When ESD current flows, the voltage changes propagate through the transistor network, providing feedback that ensures the circuit responds appropriately to actual ESD events while maintaining selectivity against normal operating currents.
Solution Approach 2:
The patent introduces intermediate control elements, including the gate structure of the NMOS transistor and the interconnected transistor bases and collectors, which act as mediators between the input signal and the ESD current path. These intermediaries provide additional control stages that maintain current path selectivity even as the trigger voltage is reduced.
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 effectively reduces the trigger voltage, ensuring that semiconductor elements are protected from ESD damage by allowing ESD current to flow safely, thereby enhancing the protection of semiconductor devices.
Implementation Method 1
To protect semiconductor elements from electrostatic discharge (ESD) which may flow from the outside of the semiconductor device through a pad
Data Source
AI summary
The present disclosure relates to semiconductor devices. An example semiconductor device includes a first well region and a second well region isolated from each other by a first device isolation film; an NPN transistor provided by a first collector region formed in the first well region and including first conductivity-type impurities, and a first emitter region formed in the second well region and including the first conductivity-type impurities; a PNP transistor provided by a second emitter region formed in the first well region and including second conductivity-type impurities different from the first conductivity-type, and a second collector region formed in the second well region and including the second conductivity-type impurities; and an NMOS transistor including a source region and a drain region formed in the second well region and including the first conductivity-type impurities, and a gate structure disposed between the source region and the drain region.