SiC Guard Ring and Dielectric Trench Layout for Breakdown Resistance
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Solution Overview
Problem
Existing silicon carbide devices face voltage breakdown issues due to high potential differences, and increasing guard rings horizontally limits their effectiveness and increases device size without significant improvement in voltage endurance.
Innovation Solution
A silicon carbide power device with alternately distributed upper and lower guard rings and dielectric trench structures, formed using a self-aligned manufacturing process, enhances electric field balance and ion implantation depth, improving voltage endurance without excessive space occupation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the number of guard rings is increased horizontally, then the voltage breakdown resistance is improved, but the device size increases and the effect of avoiding voltage breakdown is limited
Solution Approach 1:
The patent transitions from a single horizontal layer of guard rings to multiple vertical layers (first guard rings at a first depth, second guard rings at a second depth). This dimensional change allows the device to accommodate more guard rings within the same horizontal footprint by utilizing the vertical dimension, thereby improving voltage breakdown resistance without proportionally increasing device area.
Solution Approach 2:
The patent embeds the second guard rings within the substrate at a different depth level than the first guard rings, creating a nested multi-layer structure. This nesting approach allows guard rings to be stacked vertically rather than spread horizontally, increasing the effective number of guard rings while maintaining a compact device footprint.
2Reliability
If the total length of the guard ring region is extended, then more guard rings can be added, but the guard rings become too far away from the JTE and the effect is limited
Solution Approach 1:
By introducing vertical layering with guard rings at different depths (first depth and second depth), the patent reduces the horizontal distance between guard rings and the JTE region. The multi-layer configuration allows guard rings to be positioned closer to the JTE in the vertical dimension, improving voltage endurance without requiring excessive horizontal extension.
Solution Approach 2:
The patent applies different spatial configurations to different regions: first guard rings are positioned at a first depth in certain areas, while second guard rings are positioned at a second depth in other areas. This localized variation in guard ring positioning optimizes the electric field distribution and voltage endurance in different regions of the device.
3Reliability
If ion implantation is performed to increase ion concentration in guard rings, then voltage division capability is improved, but the manufacturing process complexity increases
Solution Approach 1:
The patent performs ion implantation to form the first guard rings before forming the second guard rings. This preliminary action allows the first guard rings to be pre-doped with appropriate ion concentrations, and subsequent processing steps can then form the second guard rings without requiring additional ion implantation, thereby improving voltage division capability while controlling manufacturing complexity.
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 solution achieves higher breakdown voltage and more uniform electric field distribution, enhancing voltage endurance while reducing the area occupied by guard rings, thus improving device performance and reducing costs.
Implementation Method 1
multiple first ion implantation regions 102... The second ion implantation regions 106 are respectively disposed at bottoms 104a of the dielectric trench structures 104
Data Source
AI summary
A silicon carbide power device includes a silicon carbide substrate, a plurality of first ion implantation regions, a plurality of dielectric trench structures, and a plurality of second ion implantation regions. The first ion implantation regions are distributed on a surface of the silicon carbide substrate in a termination region. The dielectric trench structures are disposed in the silicon carbide substrate among the first ion implantation regions, so that the dielectric trench structures and the first ion implantation regions are alternately arranged along a horizontal direction. The second ion implantation regions are respectively disposed at the bottoms of the dielectric trench structures.