SiC Power MOSFET Edge Ring with Auto-Aligned Variable Transparency
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Solution Overview
Problem
The use of hard masks for forming edge termination regions in silicon carbide (SiC) wafers leads to planarity issues and limits the minimum separation distance between implanted regions, making it difficult to achieve desired doping profiles and breakdown voltage distributions.
Innovation Solution
A method involving intentional damage to the semiconductor surface through non-reactive ion implantation to alter the channeling effect, allowing for the formation of edge termination regions with variable transparency without the need for high-energy implants and hard masks, enabling closer spacing of implanted sub-regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If hard masks are used for forming edge termination regions, then local shielding during implant is achieved, but planarity problems occur and minimum separation distance between implanted regions is limited
Solution Approach 1:
The patent applies preliminary action by performing a first ion implantation to create damaged regions that serve as placeholders for future implanted sub-regions. These damaged regions are formed before the actual edge termination implant, allowing subsequent implants to be performed without hard masks while maintaining precise spatial control through the auto-aligned nature of the process
Solution Approach 2:
The patent extracts the masking function from physical hard masks by using intentionally damaged regions that serve as virtual masks. The damaged regions created by the first implant replacement process effectively define where subsequent implants will occur, eliminating the need for separate hard mask layers and their associated planarity problems
2Manufacturing precision
If hard masks are used for forming edge termination regions, then local shielding is achieved, but the mutual spatial distance between adjacent implants is limited
Solution Approach 1:
The first ion implantation creates damaged regions that predefine the locations of future implanted sub-regions. This preliminary action allows subsequent implants to be performed with greater flexibility in spacing, as the damaged regions serve as auto-aligned templates that eliminate the need for hard mask-defined spacing constraints
Solution Approach 2:
The damaged regions act as an intermediary between the implantation process and the final edge termination structure. These regions serve as a intermediary step that captures the spatial configuration information needed for subsequent implants, allowing closer spacing than would be possible with hard mask constraints
3Length of stationary object
If channeled implant is used to reach desired depth, then doping depth is increased, but channeling effect causes unpredictable ion penetration
Solution Approach 1:
The patent applies preliminary anti-action by intentionally creating damaged regions that counteract the channeling effect. These damaged regions, formed by the first ion implantation, disrupt the crystal lattice structure in a controlled manner, preventing subsequent ions from following channeling paths and thereby controlling penetration depth more predictably
Solution Approach 2:
The patent converts the harmful channeling effect into a beneficial control mechanism. By intentionally creating damaged regions that disrupt channeling, the process transforms the unpredictable deep penetration caused by channeling into a controlled implantation process where depth is determined by the damaged region structure rather than crystal orientation
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 approach allows for improved electric field distribution and increased breakdown voltage without planarity issues, enabling more efficient and precise doping profiles in SiC-based electronic devices.
Implementation Method 1
the so-called channeling may considerably increase the penetration depth of the ions into the crystalline material with respect to an amorphous target. This phenomenon may occur if the direction of the impinging ion beam is nearly parallel to the main crystallographic axes or planes
Implementation Method 2
Ion implant is nowadays a well-established technique for introducing dopants into Silicon Carbide, SiC
Data Source
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AI summary
Method for manufacturing an electronic device (40), comprising the steps of: arranging a semiconductor body (50) of N-type, having a lattice structure with spatial symmetry; forming, in the semiconductor body, a damaged region (80a) having an amorphous structure or a structure with no spatial symmetry; forming an edge termination region (68) of P-type in the semiconductor body (50) including performing a channelized implant of P-type doping species at the damaged region and at portions of the semiconductor body adjacent to the opposite sides of the damaged region.