SiC Edge Termination Structure With Floating Rings for Stable Breakdown
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Solution Overview
Problem
Existing semiconductor devices face challenges in designing effective edge termination structures for SiC power devices due to low dopant diffusion coefficients, high interface trap levels, and breakdown voltage instabilities, which limit their high-voltage performance and reliability.
Innovation Solution
The semiconductor device incorporates a termination area with laterally spaced apart P-type floating rings defined by etching, surrounded by recessed N+ implanted regions and additional P+ doped regions, which enhance insulation and prevent inversion, thereby stabilizing the electric field distribution and improving device performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high dose implantation is used to define P doped areas, then activation of P dopant is improved, but crystal damage and surface damage increase
Solution Approach 1:
The patent changes the doping method from high-dose implantation to in-situ doped epitaxial growth, fundamentally altering the process parameters to achieve dopant activation without the harmful crystal damage associated with high-dose implantation
Solution Approach 2:
The patent replaces the mechanical implantation process with a chemical epitaxial growth process, where dopants are incorporated during crystal formation, avoiding the physical damage caused by ion bombardment in implantation
2Length of stationary object
If deep junctions are implemented, then termination depth is improved, but lateral dopant diffusion is limited
Solution Approach 1:
The patent changes the doping mechanism from diffusion-based implantation to in-situ doped epitaxial growth, enabling precise control of dopant concentration and depth without relying on lateral diffusion, thus achieving deep junctions with controlled lateral distribution
3Ease of manufacture
If standard Si termination architectures are used, then manufacturing simplicity is maintained, but breakdown voltage stability deteriorates due to interface traps
Solution Approach 1:
The patent employs a composite structure combining P-type floating rings with N-type drift region, creating a heterostructure that compensates for interface trap effects and stabilizes the electric field distribution at the termination area
Solution Approach 2:
The P-type floating rings act as intermediary structures between the active area and the passivation interface, mediating the electric field distribution and reducing the impact of interface traps on breakdown voltage stability
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 design achieves improved breakdown voltage stability, enhanced ruggedness against surface charges, and increased reliability in high-voltage applications, addressing the limitations of traditional edge termination structures.
Implementation Method 1
stabilizing the electric field distribution and improving device performance
Data Source
Figure 1a~1b
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Figure 3a~3b
AI summary
A semiconductor device, comprising a semiconductor body comprising a semiconductor substrate and an epitaxial layer formed on the semiconductor substrate, said epitaxial layer being of the first conductivity type, and wherein an active area and a termination area adjacent the active area are arranged in the epitaxial layer, wherein said termination area comprises a plurality of laterally spaced apart first regions, said first regions being of the second conductivity type opposite to said first conductivity type, each of said plurality of first regions enclosing, observed from a top view of said semiconductor device, said active area and one or more second regions, wherein said second regions are comprised in between said plurality of spaced apart first regions, respectively, wherein said one or more second regions extend further into said epitaxial layer than said plurality of spaced apart first regions, and wherein said one or more second regions comprise an insulation material for insulating said plurality of spaced apart first regions from one another.