Floating Diffusion Layer for Electric Field Relaxation in Semiconductor Edge Termination
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Solution Overview
Problem
Conventional semiconductor apparatuses used in ignition systems for internal combustion engines face breakdown issues due to high voltage inputs exceeding 400 V, causing electric field concentration and potential device failure.
Innovation Solution
A semiconductor apparatus with an edge termination region, a protective diode, and a diffusion layer with a floating potential is designed. The diffusion layer is placed between the edge termination region and the protective diode, diffusing electric fields and preventing breakdown by maintaining a conductivity type opposite to the substrate, thereby enhancing the device's reliability under high voltage conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a protective diode is provided between the collector and gate of the power semiconductor device to achieve high breakdown voltage, then the breakdown voltage can reach approximately 400 V, but electric fields concentrate in the surrounding region of the protective diode when high voltage exceeds 400 V is input, causing potential device breakdown
Solution Approach 1:
A diffusion layer with floating potential is introduced as an intermediary structure between the protective diode and the edge termination region. This diffusion layer acts as a mediator that redistributes the electric field, preventing concentration at critical interfaces while maintaining the protective diode's voltage clamping function.
Solution Approach 2:
The diffusion layer is strategically positioned only in the gap portion between the edge termination region aligned with the protective diode and the protective diode itself. This localized modification changes the electric field distribution characteristics specifically in the high-stress region without affecting other areas of the device structure.
2Ease of manufacture
If the diffusion layer is provided only in the gap portion between the edge termination region and the protective diode, then the device structure is simplified and manufacturing is easier, but the electric field distribution may not be optimized
Solution Approach 1:
The diffusion layer is strategically positioned only in the gap portion between the edge termination region aligned with the protective diode and the protective diode itself. This localized modification changes the electric field distribution characteristics specifically in the high-stress region without affecting other areas of the device structure.
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 semiconductor apparatus effectively prevents electric field concentration and breakdown, improving reliability and performance by diffusing electric fields and maintaining a stable potential distribution, as demonstrated by reduced leakage currents during reliability tests.
Implementation Method 1
a diffusion layer that has a floating potential and is formed in the semiconductor substrate on the first surface side thereof, where the diffusion layer is provided in a gap portion between a region of the edge termination region that is aligned with the protective diode and the protective diode
Data Source
AI summary
A semiconductor apparatus includes a semiconductor substrate, a semiconductor element, an edge termination region that surrounds the semiconductor element, a protective diode that has a first terminal and a second terminal, where the first terminal is positioned within the edge termination region and the second terminal is positioned outside the edge termination region, and a diffusion layer that has a floating potential, where the diffusion layer is provided in a gap portion between a region of the edge termination region that is aligned with the protective diode and the protective diode.