SiC Power Device Termination Structure for Breakdown Voltage
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional power devices require an extra buffer layer to withstand breakdown voltage, increasing manufacturing complexity and leaving room for improvement in voltage capability.
Innovation Solution
A silicon carbide power device with a termination structure comprising a silicon carbide substrate, a power element structure, and a termination structure featuring at least one first doped ring with a lower doping concentration and greater doping depth, and a second doped ring with a higher doping concentration and depth, eliminating the need for an extra buffer layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an extra buffer layer is added to withstand breakdown voltage, then the voltage withstanding capability is improved, but the device complexity and manufacturing process complexity increase
Solution Approach 1:
The invention merges the buffer layer function and termination structure function into a single integrated termination structure. The termination structure includes a first doped region with a first doping concentration and a second doped region with a second doping concentration, where the doping concentration gradually increases from the drift layer toward the outer region. This gradient doping structure simultaneously achieves voltage withstanding capability and electric field termination without requiring a separate buffer layer, thus reducing device complexity while maintaining reliability.
Solution Approach 2:
The invention changes the doping concentration parameter gradually from the first doped region to the second doped region, creating a gradient structure. The first doping concentration is lower than the second doping concentration, forming a continuous transition that effectively terminates the electric field and distributes the voltage stress. This parameter change approach achieves the buffer layer effect within the termination structure itself, eliminating the need for an extra buffer layer and reducing manufacturing complexity.
2Reliability
If an extra buffer layer is added to enhance breakdown voltage capability, then the voltage withstanding capability is improved, but the manufacturing cost and process complexity increase
Solution Approach 1:
The invention combines the buffer layer formation process with the termination structure formation process into a single manufacturing step. By using implantation or in-situ doping to create the gradient-doped termination structure, the patent eliminates the need for separate buffer layer fabrication processes such as epitaxial growth or additional ion implantation steps. This merging of processes reduces manufacturing complexity and cost while achieving the same voltage withstanding capability.
Solution Approach 2:
The gradient doping profile (first doping concentration < second doping concentration) is achieved through controlled implantation or in-situ doping processes that can be integrated into existing termination structure fabrication. This parameter-based approach allows the termination structure to inherently provide voltage withstanding capability without requiring additional process steps, thereby improving ease of manufacture while maintaining high breakdown voltage capability.
3Ease of manufacture
If a conventional termination structure is used, then the manufacturing process is simple, but the breakdown voltage withstanding capability is insufficient
Solution Approach 1:
The invention introduces a gradient doping concentration parameter into the termination structure, where the doping concentration increases from the first doped region to the second doped region. This parameter change enhances the electric field distribution and voltage withstanding capability while maintaining compatibility with conventional manufacturing processes such as implantation or in-situ doping. The gradient structure achieves superior voltage capability without sacrificing manufacturing simplicity.
Solution Approach 2:
The invention applies different doping concentrations at different locations within the termination structure. The first doped region has a lower doping concentration closer to the drift layer, while the second doped region has a higher doping concentration at the outer region. This local quality variation optimizes the electric field distribution throughout the structure, enhancing breakdown voltage capability while using standard manufacturing techniques.
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 capability to withstand breakdown voltage without additional manufacturing steps, improving reliability and reducing costs while achieving higher breakdown voltages through optimized electric field distribution.
Implementation Method 1
the first doped ring has a first doping concentration smaller than that of the second doped ring and a first doping depth greater than that of the second doped ring... the termination structure has greater capability to withstand the breakdown voltage... optimized electric field distribution
Data Source
AI summary
A silicon carbide power device equipped with termination structure comprises a silicon carbide substrate, a power element structure and a termination structure. The silicon carbide substrate contains a drift layer which has a first conductivity and includes an active zone and a termination zone. The power element structure is located in the active zone. The termination structure is located in the termination zone and has a second conductivity, and includes at least one first doped ring abutting and surrounding the power element structure and at least one second doped ring surrounding the first doped ring. The first doped ring has a first doping concentration smaller than that of the second doped ring and a first doping depth greater than that of the second doped ring, thereby can increase the breakdown voltage of the silicon carbide power device.