Trench Contact Layout for Semiconductor Latch-Up Suppression
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Solution Overview
Problem
Existing semiconductor devices face challenges in improving latch-up withstand capability during switching, particularly due to the formation of parasitic thyristors that can lead to unwanted triggering and reduced operational stability.
Innovation Solution
The semiconductor device incorporates a specific design with alternating first and second contact portions, where the second contact portion extends below the emitter region to avoid direct hole extraction, thereby preventing the formation of NPNP-type parasitic thyristors and enhancing latch-up resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the contact region is provided below a lower end of an emitter region, then latch-up withstand capability is improved, but device complexity increases due to additional structural design requirements
Solution Approach 1:
The contact region is divided into two distinct segments: a first contact portion positioned above the lower end of the emitter region, and a second contact portion positioned below the lower end of the emitter region. This segmentation allows each contact portion to serve specific functions in preventing parasitic thyristor formation while maintaining overall structural organization and reducing design complexity.
Solution Approach 2:
Different regions of the contact structure are assigned different properties and positions. The first contact portion is located at a specific position relative to the emitter region to provide one function, while the second contact portion is located at another position to provide a different function. This local differentiation optimizes latch-up prevention while maintaining manufacturing feasibility.
2Reliability
If the second contact portion extends below the emitter region to prevent parasitic thyristor formation, then latch-up resistance is enhanced, but manufacturing precision requirements increase
Solution Approach 1:
The first contact portion is formed in advance during the manufacturing process, establishing a reference structure before the second contact portion is created. This preliminary action simplifies subsequent manufacturing steps by providing a established framework that guides the formation of the second contact portion, thereby reducing the overall precision requirements.
Solution Approach 2:
The first contact portion acts as an intermediary element between the emitter region and the second contact portion. It provides a intermediate reference structure that facilitates the precise positioning of the second contact portion without requiring direct high-precision alignment between the emitter region and the second contact portion, thus reducing manufacturing precision requirements.
3Productivity
If alternating first and second contact portions are implemented, then hole extraction efficiency is improved, but device area increases
Solution Approach 1:
The contact structure is segmented into alternating first and second contact portions positioned at different locations relative to the emitter region. This segmentation creates multiple pathways for hole extraction, improving efficiency by distributing the extraction function across multiple discrete contact regions rather than requiring a single large contact area.
Solution Approach 2:
Instead of increasing the lateral area of contact regions, the solution utilizes the vertical dimension by positioning contact portions at different depths and locations relative to the emitter region. This dimensional approach allows multiple contact portions to be arranged in a compact footprint while providing enhanced hole extraction capability through their alternating configuration.
Data Source
AI summary
Provided is a semiconductor device including a gate trench portion and a first trench portion adjacent to the gate trench portion. The device may include a first conductivity type drift region provided in a semiconductor substrate, a second conductivity type base region provided above the drift region, a first conductivity type emitter region provided above the base region and having a doping concentration higher than that of the drift region, and a second conductivity type contact region provided above the base region and having a doping concentration higher than that of the base region. The contact region includes a first contact portion provided on a front surface of the substrate, and a second contact portion having a doping concentration different from that of the first contact portion and provided alternately with the first contact portion in a trench extending direction on a side wall of the first trench portion.