Dummy Contact Plugs for High Voltage Breakdown
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Solution Overview
Problem
Current semiconductor manufacturing processes for high voltage MOS transistor devices, such as LDMOS, face challenges in achieving high breakdown voltage and reliability due to limitations in electric field distribution and device structure.
Innovation Solution
The semiconductor structure incorporates dummy plugs within the dummy contact that decrease in depth towards the drain region, effectively dispersing the electric field and increasing breakdown voltage, while the manufacturing method involves forming these plugs on a substrate with a specific depth and width gradient.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional dummy contact structures are used, then manufacturing is simple, but breakdown voltage is insufficient
Solution Approach 1:
The dummy contact is divided into multiple dummy plugs with different depths instead of a single uniform structure. This segmentation allows the electric field to be distributed across multiple interfaces, effectively increasing the breakdown voltage while maintaining a manageable structural complexity.
Solution Approach 2:
Different regions of the dummy contact have different plug depths, creating local variations in the structure. The shallower plugs are positioned closer to the drain region where higher electric field intensity occurs, providing localized field distribution optimization that enhances overall breakdown voltage.
2Reliability
If uniform depth dummy plugs are used, then manufacturing is easier, but electric field distribution is poor
Solution Approach 1:
The dummy plug depths are varied dynamically across the structure rather than maintaining a static uniform depth. This dynamic variation in plug depth creates optimal electric field distribution by positioning shallower plugs in high-field regions and deeper plugs in lower-field regions, improving reliability while the variation follows a systematic pattern that remains manufacturable.
3Strength
If deeper dummy plugs are used throughout, then breakdown voltage increases, but manufacturing complexity increases
Solution Approach 1:
Instead of uniformly increasing all plug depths, the invention applies different depths locally based on position. Shallower plugs are used in regions closer to the drain where they provide sufficient field distribution, while deeper plugs are used in other regions. This local optimization achieves high breakdown voltage without the excessive complexity of uniformly deep plugs throughout the entire structure.
Data Source
AI summary
A semiconductor structure and a manufacturing method thereof are provided. The semiconductor structure includes a substrate, a source region, a drain region, a gate, and a dummy contact. The source region and the drain region are formed in the substrate. The gate is formed on the substrate and between the source region and the drain region. The dummy contact includes a plurality of dummy plugs formed on the substrate, wherein the dummy plugs have depths decreasing towards the drain region.