Semiconductor ESD Protection Circuit With Shared Transistor Bases
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Solution Overview
Problem
Existing semiconductor devices face challenges in effectively protecting internal semiconductor elements from electrostatic discharge (ESD) due to high trigger voltages in ESD protection circuits, which can lead to damage during ESD events.
Innovation Solution
The semiconductor device incorporates a novel ESD protection circuit design where the base of the PNP transistor and NPN transistor are electrically connected, allowing the ESD protection circuit to be triggered at a lower voltage than the breakdown voltage level, and includes a diode to reduce parasitic capacitance and improve turn-on performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the ESD protection circuit uses conventional transistor configuration, then the breakdown voltage provides protection, but the trigger voltage is too high to effectively protect semiconductor elements
Solution Approach 1:
The patent introduces a base connection structure as an intermediary element between the PNP and NPN transistors. By electrically connecting the bases of both transistors, a new current path is created that enables earlier triggering of the ESD protection circuit. This base connection acts as a mediator that allows the circuit to respond to lower voltage stress conditions, thereby reducing the trigger voltage while maintaining effective ESD protection.
2Ease of manufacture
If the ESD protection circuit is designed with standard transistor layout, then manufacturing is straightforward, but parasitic capacitance remains high affecting high-speed signal integrity
Solution Approach 1:
The patent addresses parasitic capacitance by strategically positioning the base connection in the vertical dimension of the transistor structure. By connecting the bases at a specific depth within the semiconductor substrate, the design reduces the overlapping area between charged regions, thereby minimizing parasitic capacitance without complicating the horizontal layout. This vertical dimension optimization allows standard manufacturing processes to be used while achieving lower parasitic effects.
3Ease of operation
If the ESD protection circuit uses isolated transistor bases, then each transistor operates independently, but the turn-on response is delayed
Solution Approach 1:
The patent merges the base operations of the PNP and NPN transistors by electrically connecting them. This combination allows the bases to respond collectively to incoming ESD stress, enabling faster turn-on response. The merged base structure ensures that when voltage stress is applied, both transistors are triggered simultaneously through the shared base connection, eliminating the delay that would occur if the transistors had to trigger independently in sequence.
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 design effectively lowers the trigger voltage of the ESD protection circuit, ensuring internal semiconductor elements are protected from ESD while reducing parasitic capacitance and maintaining high-speed signal integrity.
Implementation Method 1
In order to protect semiconductor elements from electrostatic discharge (ESD) that may occur in a pad, a receiving circuit, a transmitting circuit, and the like may be connected to an ESD protection circuit.
Implementation Method 2
includes a diode to reduce parasitic capacitance and improve turn-on performance
Data Source
AI summary
A semiconductor device includes a substrate doped with first conductivity-type impurities, a first well doped with second conductivity-type impurities different from the first conductivity-type impurities, first active regions in the first well, the first active regions being doped with the first conductivity-type impurities and connected to a first pad through a first interconnection, second active regions outside the first well, the second active regions being doped with the second conductivity-type impurities and connected to a second pad through a second interconnection, third active regions around the first active regions in the first well and doped with the second conductivity-type impurities, and fourth active regions around the second active regions outside the first well and doped with the first conductivity-type impurities, wherein at least one of the third active regions and at least one of the fourth active regions are electrically connected to each other through a third interconnection.