Semiconductor Emitter Region Curved Boundary Latch-Up
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Solution Overview
Problem
Conventional semiconductor devices with increased emitter region width for channel formation lead to larger voltage drops and latch-up issues due to increased hole movement in the base region.
Innovation Solution
A semiconductor device design featuring a semiconductor substrate with trench portions, an emitter region, and a contact region, where the emitter region's central length is shorter than its length at trench contacts, and the contact region's depth decreases away from trench portions, with a curved emitter region boundary and separated contact regions, to reduce hole concentration and voltage drop.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the width of the emitter region is increased to reserve channel formation region, then the channel formation area is improved, but the voltage drop in the base region increases and latch-up occurs more easily
Solution Approach 1:
The emitter region is designed with non-uniform width: wider at the ends (near trench portions) to ensure channel formation, and narrower at the central position to reduce hole movement distance and voltage drop in the base region. This local variation in dimensions resolves the contradiction between maintaining channel area and preventing latch-up.
Solution Approach 2:
The contact region is extended in the depth direction (vertical dimension) with gradually decreasing depth from trench portions toward the center. This vertical extension compensates for the reduced horizontal width at the center, maintaining effective contact area while allowing the emitter region to be narrower and reducing latch-up risk.
2Reliability
If the emitter region width is increased to ensure channel formation, then the channel formation capability is improved, but the hole movement distance in the base region increases causing larger voltage drop
Solution Approach 1:
The emitter region width is locally optimized: wider at ends for channel formation, narrower at center for reduced voltage drop. This spatially varying geometry simultaneously achieves both objectives.
3Area of stationary object
If the emitter region is made wider for channel formation, then the channel area is improved, but the device complexity increases due to curved boundaries and varied dimensions
Solution Approach 1:
The emitter region boundary is designed with curved shapes rather than straight lines, creating a smooth transition between wide and narrow sections. This curved geometry achieves the required non-uniform width distribution while being manufacturable and avoiding excessive complexity.
Data Source
AI summary
It is aimed to realize both of reserving a channel formation region and suppressing a latch-up. A semiconductor device is provided, including: a semiconductor substrate; a plurality of trench portions provided at a front surface side of the semiconductor substrate, each of which has a portion extending in an extending direction; and a first conductivity-type emitter region and a second conductivity-type contact region provided between adjacent two trench portions and exposed on a front surface of the semiconductor substrate alternately in the extending direction, wherein on the front surface of the semiconductor substrate, a length of the emitter region at a central position between the two trench portions is shorter than a length of the emitter region at portions contacting the trench portions, and on the front surface of the semiconductor substrate, at least a part of a boundary of the emitter region has a curved shape.