Semiconductor Structure for Low-Voltage ESD Protection

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Solution Overview

Problem

Conventional silicon control rectifier (SCR) devices have a high turn-on voltage, exceeding the breakdown voltage of low-voltage devices, making them inadequate for protecting low-voltage integrated circuits from electrostatic discharge (ESD) damage.

Innovation Solution

A semiconductor structure incorporating a silicon control rectifier (SCR) region and a NPN region, with specific well and implant regions, and metal interconnections, is designed to reduce the turn-on voltage by forming efficient ESD current paths, allowing for effective ESD protection at lower voltages.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional SCR devices are used for ESD protection, then ESD protection capability is provided, but the turn-on voltage is too high (about 20 V) to protect low-voltage devices

Engineering Contradiction:

ImproveESD protection capabilityVSAvoidturn-on voltage

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent combines an SCR region and a NPN region into a single integrated semiconductor structure. The SCR region provides ESD protection functionality while the NPN region (with its lower breakdown voltage) enables the structure to activate at lower voltages (5-15 V range), thus protecting low-voltage devices effectively

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent creates different functional regions with distinct properties: the SCR region is optimized for ESD protection with specific p-well and n-well structures, while the NPN region is optimized for low-voltage operation. Each region has tailored doping concentrations and geometries to achieve its specific function, with the overall structure activating at lower voltages than conventional SCR devices

Inventive Principle:

Principle #3Local quality

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 semiconductor structure achieves a lower turn-on voltage of approximately 5 V to 15 V, enabling effective protection of low-voltage devices from ESD damage, compared to conventional SCR devices which require voltages above 20 V.

Implementation Method 1

Electrostatic discharge (ESD) is usually characterized by fast transient high voltage discharge. An ESD event can occur in electrical circuits, such as an integrated circuit.

Methodology Applied

Scientific EffectElectrostatic discharge: Electrostatic Discharge

Data Source

PatentUS10580765B1Semiconductor structure for electrostatic discharge protection

Publication Date: 2020.03.03 NAN YA TECH

AI summary

A semiconductor structure includes a silicon control rectifier (SCR) region and a NPN region adjacent to the SCR region. The silicon control rectifier (SCR) region includes a first p-well region, a first n-well region surrounded by the first p-well region and a first P+ region in the first p-well region and spaced apart from the first n-well region. The NPN region includes a second p-well region, a first N+ region, a second N+ region and a second P+ region. The first N+ region is coupled to the second p-well region and an electrostatic discharge source. The second N+ region is coupled to the second p-well region and spaced apart from the first N+ region. The second P+ region is disposed in the second p-well region and equipotentially connected to the first P+ region in the first p-well region.