High-Voltage MOSFET ESD Robustness via Racetrack Doping
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Solution Overview
Problem
High-voltage MOSFETs have weak electrostatic discharge (ESD) robustness due to non-uniform electric field distribution and local current crowding, making them vulnerable to ESD stress, and enlarging the device to improve robustness is not cost-effective.
Innovation Solution
Integration of an ESD protection device with a heavily-doped drain region and doped regions formed in a racetrack pattern to surround the drain region, along with an ESD protection device featuring doped regions in a second racetrack pattern to surround a heavily-doped region, providing quicker ESD triggering and smoother electric field distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the device size is enlarged to reduce maximum electric field and current crowding effect, then ESD robustness is improved, but silicon area requirement increases and cost-effectiveness deteriorates
Solution Approach 1:
The patent applies local quality by introducing a lightly-doped drain extension region specifically at the drain end where current crowding occurs. This localized doping modification creates a more uniform electric field distribution precisely where needed, without requiring overall device enlargement. The selective doping concentration change addresses the local field non-uniformity problem while maintaining compact device dimensions.
Solution Approach 2:
The patent changes the doping concentration parameter by introducing a lightly-doped drain extension region with lower doping concentration than the heavily-doped drain region. This parameter change modifies the electric field distribution characteristics, reducing peak fields and current crowding effects. The doping concentration gradient creates optimal field distribution for ESD robustness without increasing device area.
2Reliability
If the device size is enlarged to reduce maximum electric field and current crowding effect, then ESD robustness is improved, but device complexity increases
Solution Approach 1:
The patent applies local quality by introducing a lightly-doped drain extension region specifically at the drain end where current crowding occurs. This localized doping modification creates a more uniform electric field distribution precisely where needed, without requiring overall device enlargement. The selective doping concentration change addresses the local field non-uniformity problem while maintaining compact device dimensions.
Solution Approach 2:
The patent merges the drain region with a lightly-doped extension portion, combining two doped regions into a unified drain structure. This merging approach integrates the ESD protection function directly into the existing drain region rather than adding separate protection devices, thereby reducing overall device complexity while improving ESD robustness.
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
Enhances the ESD robustness of high-voltage MOSFETs by reducing the likelihood of local current crowding and improving electric field distribution, allowing them to withstand higher ESD stress without damage.
Implementation Method 1
non-uniformity of electric field distribution and local current crowding effect at a discontinuous region inside the high-voltage MOSFET
Implementation Method 2
electrostatic discharge (ESD) protection so it can withstand ESD stress caused by its external environment
Data Source
AI summary
An embodiment provides a semiconductor device integrated with a switch device and an ESD protection device, having electrostatic discharge robustness. Formed on a semiconductor substrate of a first type is a drain region of a second type opposite to the first type. The switch device has a source region of the second type, formed on the semiconductor substrate and with a first arch portion facing inwardly toward a first direction. The first arch portion partially surrounds the drain region. A control gate of the switch device controls electric connection between the drain region and the source region. The ESD protection device comprises a first region and a second region, both of the first type. The first region adjoins the drain region. The second region has a second arch portion facing inwardly toward a second direction opposite to the first direction, and the second arch portion partially surrounds the first region.