ESD Protection Semiconductor Devices with Segmented N-Regions
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Solution Overview
Problem
Integrated circuits face challenges in safely dissipating high currents during electrostatic discharge (ESD) or surge events without incurring damage, and existing protection devices often increase parasitic capacitance, which can interfere with normal operations.
Innovation Solution
The semiconductor device design includes multiple n-type semiconductor regions with circular, oval, or obround footprints spaced apart from isolation structures, connected to terminals, and a p-type semiconductor layer with a buried region and graded dopant profiles to form low capacitance diodes that facilitate uniform current distribution and high current handling capability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If protection devices are added to protect ICs during ESD or surge events, then current handling capability is improved, but parasitic capacitance increases which interferes with normal operations
Solution Approach 1:
The protection device is divided into multiple discrete n-type semiconductor regions (first, second, third, and fourth regions) with distinct footprints and contact groups. Each region can be independently optimized for its specific function, allowing the overall device to provide comprehensive protection while minimizing total parasitic capacitance through efficient spatial arrangement and sizing of individual regions.
2Reliability
If the protection device handles high current during ESD events, then reliability is improved, but thermal runaway risk increases
Solution Approach 1:
The n-type semiconductor regions are spatially segmented and each connects to separate contact groups that can be distributed across the device structure. This segmentation allows current to be divided and conducted through multiple parallel paths, preventing current concentration in a single location and thereby reducing localized heating and thermal runaway risk.
Solution Approach 2:
The patent utilizes vertical layering with the n-type regions positioned at different depths within the semiconductor structure, with some regions extending to different surfaces. This three-dimensional arrangement provides additional current conduction pathways in the vertical dimension, further distributing current density and reducing thermal hotspots.
3Area of stationary object
If n-type semiconductor regions are positioned closer to isolation structures to reduce area, then device area is reduced, but current spreading capability deteriorates
Solution Approach 1:
The n-type semiconductor regions are positioned at different vertical levels within the semiconductor structure, with some regions located at first surfaces and others at second surfaces of the substrate. This vertical separation allows the regions to be spaced apart in the third dimension while maintaining compact lateral footprint, thereby preserving current spreading capability without increasing device area.
Solution Approach 2:
Multiple n-type regions are distributed across different locations and depths within the semiconductor structure, with each region having its own contact groups. This segmentation enables current to spread through multiple discrete pathways throughout the volume of the device, maintaining effective current distribution while keeping the lateral footprint compact.
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 design enhances current spreading and handling capability, reducing the risk of thermal runaway and maintaining low capacitance, thereby improving ESD protection while minimizing interference with normal circuit operations.
Implementation Method 1
p-type layer over the n-type layer; a first area including a plurality of n-type regions in the p-type layer
Implementation Method 2
enhances current spreading and handling capability, reducing the risk of thermal runaway
Data Source
AI summary
Semiconductor devices with high current capability for ESD or surge protection are described. The semiconductor device includes multiple n-type semiconductor regions in a p-type semiconductor layer. Each of the n-type semiconductor regions may have a footprint with a circular, oval, or obround shape. Moreover, a boundary of the footprint may be spaced apart from an isolation structure that surrounds the p-type semiconductor layer. The n-type semiconductor regions may be coupled to a terminal through individual groups of contacts that are connected to the n-type semiconductor regions, respectively. Additionally, or alternatively, the p-type semiconductor layer surrounded by the isolation structure may not include any re-entrant corner.