Semiconductor Device Current Concentration Management
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Solution Overview
Problem
Semiconductor devices, such as diodes, are prone to breakage when current flow is interrupted due to current concentration at specific portions, leading to potential device failure.
Innovation Solution
The semiconductor device design includes a specific structure with varying impurity concentrations and electrode positions to prevent current concentration, featuring a n++ type cathode region, an n-type buffer region, an n-type drift region, and an anode region with strategically positioned electrodes and insulating layers to manage current flow and reduce the likelihood of breakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If current flow is interrupted in a conventional semiconductor device, then the device can switch off, but current concentration occurs at specific portions causing breakage and reducing reliability
Solution Approach 1:
The patent applies local quality by creating non-uniform impurity concentration distributions in the drift region. Specifically, the impurity concentration is made higher at corner portions and lower at center portions of the drift region. This local variation in electrical properties redirects current flow paths away from corner regions during switching off, preventing current concentration and the associated breakage while maintaining overall device reliability.
2Ease of manufacture
If the semiconductor device structure is simplified, then manufacturing is easier, but current concentration cannot be prevented leading to device breakage
Solution Approach 1:
The patent employs parameter changes by modifying the impurity concentration parameter within the drift region. The impurity concentration is varied spatially - higher at corner portions and lower at center portions - without changing the fundamental device structure or requiring additional complex components. This parameter modification alone is sufficient to redirect current flow and prevent breakage, achieving improved reliability through a manufacturable approach.
Data Source
AI summary
A semiconductor device includes a semiconductor layer. The semiconductor layer has bottom and upper surfaces opposite to each other in a first direction. The semiconductor layer includes a first region of a first conductivity type at the bottom surface, a second region of the first conductivity type at the bottom surface surrounding the first region, a third region of the first conductivity type above the first and second regions, and a fourth region of a second conductivity type extending from the upper surface into the third region. In a first cross sectional plane along the first direction, an outer edge of the first region is within an outer edge of the fourth region by a first distance. In a second cross sectional plane along the first direction, an outer edge of the first region is within an outer edge of the fourth region by a second distance.