Semiconductor Device P-Type Region Corner Contouring
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Solution Overview
Problem
Conventional semiconductor devices face challenges with dielectric breakdown due to electric field concentration at the corner portions of the p-type region in the non-operating region, especially when the parasitic diode turns OFF, leading to reduced reverse recovery capability.
Innovation Solution
The semiconductor device incorporates a p-type region with contoured corner portions in the non-operating region, where the p-type region is connected to the source pad and has a higher impurity concentration, reducing electron hole current concentration and electric field at the corners, thereby enhancing the reverse recovery capability of the parasitic diode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a p-type region is provided in the non-operating region to form a parasitic diode, then the reverse recovery capability is improved, but dielectric breakdown occurs at the corner portions due to electric field concentration
Solution Approach 1:
The corner portions of the p-type region are contoured (rounded) instead of having sharp corners. This curvature distributes the electric field more evenly across the region, preventing electric field concentration at the corners and thereby suppressing dielectric breakdown while maintaining the reverse recovery capability of the parasitic diode.
Solution Approach 2:
The impurity concentration in the p-type region is increased specifically at the corner portions compared to the center region. This local quality enhancement strengthens the parasitic diode formation at the corners where electric field concentration would otherwise occur, improving reverse recovery capability without causing breakdown.
2Area of stationary object
If the p-type region has sharp corners to maximize the active area, then the device area is reduced, but electric field concentration at the corners causes dielectric breakdown
Solution Approach 1:
The corner portions are contoured with a rounded shape instead of sharp corners. This maintains substantially the same active area while distributing the electric field more uniformly, preventing concentration effects that would lead to dielectric breakdown.
3Manufacturing precision
If the p-type region is positioned close to the source pad to minimize distance, then the manufacturing precision is improved, but the electric field at the corners increases causing breakdown
Solution Approach 1:
The impurity concentration is increased specifically at the corner portions of the p-type region. This local enhancement allows the region to withstand higher electric field intensity that results from close positioning to the source pad, preventing dielectric breakdown while maintaining precise positioning.
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 effectively suppresses dielectric breakdown and enhances the reverse recovery capability of the parasitic diode by distributing the electron hole current evenly across the p-type region, improving the reliability and efficiency of the semiconductor device.
Implementation Method 1
electric field concentration at the corner portions of the p-type region
Data Source
AI summary
In an effective region of an active region, main semiconductor elements that are vertical MOSFETs and a source pad of the main semiconductor elements are provided. In a non-operating region of the active region, a gate pad of the main semiconductor elements is provided on a front surface of a semiconductor substrate. Directly beneath the gate pad, in a surface region of the front surface of the semiconductor substrate, a p-type region is provided spanning the non-operating region of the active region overall. The p-type region of the non-operating region of the active region is electrically connected to the source pad and forms a parasitic diode by a pn junction with an n−-type drift region when the main semiconductor elements are OFF. The p-type region of the non-operating region of the active region has a rectangular planar shape with rounded or chamfered corner portions in a planar view.