Lateral High-Voltage SCR With Integrated Negative Strike Diode
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Solution Overview
Problem
Existing silicon controlled rectifiers (SCRs) for electrostatic discharge (ESD) protection face challenges in area efficiency, often compromising performance with large separate negative strike diodes that increase leakage and capacitance concerns.
Innovation Solution
The design incorporates a concentric semiconductor region structure with an electrically non-contacted region to modulate snapback voltage and an electrically-contacted region for diodic response, reducing the need for separate negative strike diodes and minimizing area while enhancing ESD protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate negative strike diode is added to provide diodic response to negative ESD strikes, then the ESD protection capability is improved, but the device area increases and leakage current increases
Solution Approach 1:
The patent combines the negative strike diode function with the SCR structure by integrating a first diode formed within the SCR's semiconductor regions. The diode's anode is connected to the anode region and cathode to the cathode region of the SCR, allowing the same device to provide both snapback protection for positive strikes and diodic clamping for negative strikes, thereby reducing total device area while maintaining comprehensive ESD protection capability
Solution Approach 2:
The SCR device is designed to perform multiple functions: it provides snapback response to positive ESD strikes through its inherent SCR action, and simultaneously provides diodic response to negative ESD strikes through the integrated first diode. This multi-functionality eliminates the need for separate dedicated components, reducing overall device complexity and area while improving reliability
2Reliability
If a separate negative strike diode is added to provide diodic response to negative ESD strikes, then the ESD protection capability is improved, but the leakage current increases
Solution Approach 1:
The patent combines the negative strike diode function with the SCR structure by integrating a first diode formed within the SCR's semiconductor regions. The diode's anode is connected to the anode region and cathode to the cathode region of the SCR, allowing the same device to provide both snapback protection for positive strikes and diodic clamping for negative strikes, thereby reducing total device area while maintaining comprehensive ESD protection capability
Solution Approach 2:
The patent optimizes the dopant concentrations and junction depths of the semiconductor regions to control the electrical characteristics of the integrated diode. By carefully adjusting these parameters, the diode provides effective negative strike protection while maintaining low leakage current under normal operating conditions, thus improving reliability without significantly increasing harmful leakage
3Reliability
If a separate negative strike diode is added to provide diodic response to negative ESD strikes, then the ESD protection capability is improved, but the capacitance increases
Solution Approach 1:
The patent combines the negative strike diode function with the SCR structure by integrating a first diode formed within the SCR's semiconductor regions. The diode's anode is connected to the anode region and cathode to the cathode region of the SCR, allowing the same device to provide both snapback protection for positive strikes and diodic clamping for negative strikes, thereby reducing total device area while maintaining comprehensive ESD protection capability
Solution Approach 2:
The first diode is nested within the SCR structure, sharing common semiconductor regions and contacts. The diode's anode is formed in the anode region and cathode in the cathode region, both of which are already part of the SCR structure. This nesting approach eliminates the need for additional separate diode structures, thereby reducing total device capacitance while providing the required diodic response to negative strikes
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 provides robust snapback response to positive ESD strikes and diodic response to negative strikes, reducing leakage and capacitance concerns, thus improving area efficiency and protection without compromising performance.
Implementation Method 1
positioned to modulate a snapback voltage of the silicon controlled rectifier
Implementation Method 2
positioned to provide a diodic response between the at least one concentric semiconductor region in the plurality of concentric semiconductor regions and the electrically-contacted region
Implementation Method 3
ESD is the sudden flow of electricity between two objects as electrical charge transfers from one of the objects to the other
Implementation Method 4
When the trigger voltage is reached or exceeded, the desired SCR response is for the SCR to conduct, the voltage across it to drop quickly (snaps back) to a much lower holding voltage, and at the same time current through the SCR is to significantly increase
Data Source
AI summary
An SCR with a first semiconductor region and plural concentric semiconductor regions, each surrounding the first semiconductor region. The SCR also includes, surrounded by at least one concentric semiconductor region in the plurality of concentric semiconductor regions, an electrically non-contacted region of a semiconductor type and positioned to modulate a snapback voltage of the silicon controlled rectifier and an electrically-contacted region of the semiconductor type and positioned to provide a diodic response between the at least one concentric semiconductor region in the plurality of concentric semiconductor regions and the electrically-contacted region.