Semiconductor Device Outer Peripheral Breakdown Control
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Solution Overview
Problem
Conventional semiconductor devices with insulated gate bipolar transistors (IGBTs) face breakdown issues in the outer peripheral parts due to deep layers that reduce breakdown voltage and increase the likelihood of device failure when current is cut off.
Innovation Solution
The semiconductor device incorporates a deep layer in the outer peripheral part that is deeper than the base layer, with strategically adjusted distances between the deep layer, emitter region, and collector layer to lower carrier density and prevent breakdown by controlling the positional relationship between these components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a deep layer is formed in the outer peripheral part deeper than the base layer, then breakdown voltage in the outer peripheral part is lowered, but this increases the likelihood of device failure when current is cut off
Solution Approach 1:
The patent applies local quality by creating different layer configurations in different regions of the semiconductor device. Specifically, the outer peripheral part has a deep layer extending deeper than the base layer, while the element part maintains the conventional structure with collector layer on drift layer. This regional differentiation allows the outer peripheral part to have lower breakdown voltage (reducing harmful effects) while the element part maintains high breakdown voltage (ensuring reliability during normal operation).
Solution Approach 2:
The patent segments the semiconductor device into distinct functional regions: an element part containing the IGBT structure and an outer peripheral part surrounding it. The deep layer is specifically formed in the outer peripheral part, separating its electrical characteristics from the element part. This segmentation allows independent optimization of each region's breakdown characteristics.
2Reliability
If the deep layer extends deeper into the drift layer, then breakdown voltage is reduced for safety, but device performance and efficiency deteriorate
Solution Approach 1:
The patent applies local quality by limiting the deep layer's deep penetration only to the outer peripheral part, not the entire device. The element part maintains the full drift layer thickness for optimal performance, while only the outer peripheral part has the reduced effective drift layer thickness due to the deep layer. This localized approach minimizes performance degradation while achieving the safety benefit of reduced breakdown voltage in the peripheral region.
Data Source
AI summary
A semiconductor device has an element part and an outer peripheral part, and a deep layer is formed in the outer peripheral part more deeply than a base layer. When a position of the deep layer closest to the element part is defined as a boundary position, a distance between the boundary position and a position closest to the outer peripheral part in an emitter region is defined as a first distance, and a distance between the boundary position and a position of an end of a collector layer is defined as a second distance, the first distance and the second distance are adjusted such that a carrier density in the outer peripheral part is lowered based on breakdown voltage in the outer peripheral part lowered by the deep layer.