Semiconductor Device Guard Ring Flow Block
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Solution Overview
Problem
High-voltage power semiconductor devices with rated voltages exceeding 6 kV face instability in main breakdown voltage characteristics due to polarization effects from impurity ions in sealing gels, leading to unpredictable collector-emitter current and voltage.
Innovation Solution
A semiconductor device design incorporating a semiconductor substrate, a power semiconductor element, a guard ring, a semi-insulating insulation film, a dielectric film, and a flow block portion to prevent the flow of dielectric material and maintain a stable dielectric film thickness, thereby stabilizing breakdown voltage characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a dielectric film is formed to cover the semi-insulating insulation film on the guard ring, then the breakdown voltage characteristics are improved, but the dielectric material may flow out during formation, causing thickness instability and characteristic degradation
Solution Approach 1:
The flow block portion is formed in advance before dielectric film deposition to prevent material flow during the subsequent dielectric film formation process. This preliminary structural preparation ensures that the dielectric material remains confined within the intended region, maintaining thickness uniformity and preventing characteristic degradation.
Solution Approach 2:
The flow block portion acts as an intermediary barrier between the dielectric material and the outer regions. This intermediate structure prevents the dielectric material from flowing out during deposition, thereby ensuring stable film thickness and reliable breakdown voltage characteristics without requiring complex deposition control mechanisms.
2Reliability
If the dielectric film thickness is increased to improve breakdown voltage characteristics, then the electrical performance is improved, but the material flow out during formation increases, causing thickness instability
Solution Approach 1:
The flow block portion is prepared in advance to establish physical boundaries before dielectric material deposition. This preliminary action ensures that even when larger amounts of dielectric material are deposited to achieve greater thickness, the material remains confined within the defined region, maintaining thickness consistency and preventing flow-induced defects.
Solution Approach 2:
The flow block portion serves as an intermediary barrier that decouples the relationship between dielectric film thickness and material flow. By introducing this intermediate structure, the system can accommodate thicker dielectric films without proportionally increasing material flow out, thereby maintaining thickness consistency while improving breakdown voltage characteristics.
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 solution effectively prevents degradation of breakdown voltage characteristics by maintaining a stable dielectric film thickness and preventing material flow, ensuring consistent collector-emitter current and voltage performance even under high voltage conditions.
Implementation Method 1
a semi-insulating silicon nitride film of high resistance on the outer circumferential junction region (guard ring) will cause the flow of a small current at the semi-insulating silicon nitride film
Implementation Method 2
The flow block portion is formed in a third region at the first main surface located at an outer side than the second region to prevent the material that will constitute the dielectric film from flowing out
Implementation Method 3
Application of voltage across the collector and emitter causes the plus ions and minus ions of the impurity ions in the silicone gel to gather at the ground side and the high potential side, respectively, to develop polarization
Data Source
AI summary
A semiconductor device includes a semiconductor substrate of a first conductivity type, including a first main surface and a second main surface opposite to each other. A power semiconductor element includes a first electrode in a first region at the first main surface of the semiconductor substrate, and a second electrode at the second main surface. A current flows between the first electrode and the second electrode. The semiconductor device also includes a guard ring of a second conductivity type, in a second region at the first main surface, at a more outer circumference than the first region. A semi-insulating insulation film covers the second region. A dielectric film in the second region covers the semi-insulating insulation film. A flow block portion in a third region at the first main surface, at a more outer circumference than the second region, prevents a flow out of the dielectric film.