Non-Depletable Doping Region for Edge Reliability
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Solution Overview
Problem
Semiconductor devices face reliability and durability issues due to high hole current densities and concentrations at the edge region during reverse mode operation, where plasma is stored and charge carriers need to flow off, leading to stress and potential device failure.
Innovation Solution
A semiconductor device with a non-depletable doping region extending laterally from the cell region towards the edge of the substrate, featuring a maximal doping concentration near the cell region and a lower concentration further away, which promotes the removal of charge carriers and reduces stress at the edge, thereby enhancing reliability and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the edge region is used for plasma storage during reverse mode operation, then the device can operate in reverse mode with body diode forward conduction, but very high hole current densities and high hole concentrations are generated at the edge region causing reliability and durability issues
Solution Approach 1:
The patent applies local quality by creating a non-uniform doping profile in the edge termination region. Specifically, a first doping region with higher doping concentration is formed adjacent to the cell region, while a second doping region with lower doping concentration is formed at the edge of the semiconductor substrate. This spatial variation in doping concentration optimizes the local electrical properties to manage hole current densities and improve reliability during reverse mode operation.
Solution Approach 2:
The patent changes the doping concentration parameter across the edge termination region. By varying the doping concentration from the cell region towards the substrate edge, the electrical characteristics of the edge region are optimized. The higher doping concentration near the cell region helps manage plasma storage, while the lower concentration at the edge reduces hole current density, thereby resolving the reliability issue.
2Productivity
If all holes from the edge region flow off through the outermost source/body contact, then charge carrier removal is achieved, but very high hole current densities are reached at the edge region
Solution Approach 1:
The patent applies local quality by creating a non-uniform doping profile in the edge termination region. Specifically, a first doping region with higher doping concentration is formed adjacent to the cell region, while a second doping region with lower doping concentration is formed at the edge of the semiconductor substrate. This spatial variation in doping concentration optimizes the local electrical properties to manage hole current densities and improve reliability during reverse mode operation.
Solution Approach 2:
The non-uniform doping profile acts as an intermediary structure between the high-density plasma region near the cell and the low-density edge region. The graded doping concentration provides a transition zone that facilitates charge carrier removal while distributing the hole current density more evenly, preventing excessive current concentration at any single point.
3Productivity
If a non-depletable doping region with high doping concentration is formed near the cell region, then charge carrier removal is facilitated, but the doping must extend laterally towards the substrate edge to be effective
Solution Approach 1:
The patent applies local quality by creating a non-uniform doping profile in the edge termination region. Specifically, a first doping region with higher doping concentration is formed adjacent to the cell region, while a second doping region with lower doping concentration is formed at the edge of the semiconductor substrate. This spatial variation in doping concentration optimizes the local electrical properties to manage hole current densities and improve reliability during reverse mode operation.
Solution Approach 2:
The doping region is segmented into two distinct zones: a first doping region with higher concentration adjacent to the cell region for efficient charge carrier removal, and a second doping region with lower concentration at the substrate edge. This segmentation allows each zone to perform its specific function optimally while reducing the overall lateral extent requirements.
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 non-depletable doping region effectively reduces the load and stress at the edge of the cell region, improving the reliability and durability of semiconductor devices by facilitating faster voltage drop and optimal current flow during commutation.
Implementation Method 1
The non-depletable doping region comprises a maximal doping concentration at an area close to the cell region and a lower doping concentration of at least 10% of the maximal doping concentration at a lateral distance of more than 20 μm to a closest contact area
Data Source
AI summary
A semiconductor device includes a plurality of compensation regions of a vertical electrical element arrangement, a plurality of drift regions of the vertical electrical element arrangement and a non-depletable doping region. The compensation regions of the plurality of compensation regions are arranged in a semiconductor substrate of the semiconductor device. Further, the plurality of drift regions of the vertical electrical element arrangement is arranged in the semiconductor substrate within a cell region of the semiconductor device. The plurality of drift regions and the plurality of compensation regions are arranged alternatingly in a lateral direction. The non-depletable doping region extends laterally from an edge of the cell region towards an edge of the semiconductor substrate. The non-depletable doping region has a doping non-depletable by voltages applied to the semiconductor device during blocking operation.