Nanosheet Gate Structure With Shallow Gate-Cut Isolation
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Solution Overview
Problem
As semiconductor devices are scaled down for high integration, there is a need to reduce the formation depth of gate-cuts to simplify the etching process and improve electrical stability between contacts, while maintaining low cost and high quality.
Innovation Solution
The semiconductor device incorporates a structure with insulating layers of different materials under the gate-cut, reducing the etching depth and complexity, and includes a gate electrode that surrounds nanosheets with a gate insulating layer, enhancing electrical stability and integration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the gate-cut formation depth is reduced, then the etching process difficulty is reduced, but the electrical stability between contacts may deteriorate
Solution Approach 1:
An insulating structure is formed in advance at the bottom of the trench before the gate-cut is formed. This preliminary action provides electrical isolation between contacts, ensuring electrical stability is maintained even when the gate-cut formation depth is reduced to simplify the etching process.
Solution Approach 2:
The insulating structure acts as an intermediary element between adjacent contacts. It provides the necessary electrical isolation without requiring deep gate-cut formation, thus resolving the conflict between ease of manufacture and electrical stability by introducing a mediating component.
2Ease of manufacture
If the gate-cut formation depth is reduced, then the manufacturing cost is reduced, but the etching process margin is reduced
Solution Approach 1:
The insulating structure is formed beforehand at the trench bottom, providing a stop layer that defines the etching depth. This allows the gate-cut etching process to be performed with reduced depth and simpler parameters, lowering manufacturing costs while maintaining adequate process margin through the pre-formed insulating barrier.
3Ease of manufacture
If insulating layers of different materials are used under the gate-cut, then the etching process is simplified, but the device complexity increases
Solution Approach 1:
Different insulating materials are used at different locations within the trench structure. A first insulating material is formed at the bottom, and a second insulating material with different etching characteristics is formed above it. This local differentiation allows selective etching processes that are simpler to control, despite the multi-layer complexity.
Solution Approach 2:
The insulating structure employs composite materials with different etching rates and properties. This composite structure enables differentiated etching behavior that simplifies the gate-cut formation process, as the etch can selectively remove or stop at different material interfaces, managing complexity through material property differentiation.
Data Source
AI summary
A semiconductor device includes a substrate, a first active pattern that includes a first side wall and a second side wall opposite to the first side wall in a second horizontal direction, a first insulating structure in a first trench extending in the first horizontal direction on the first side wall of the first active pattern, a second insulating structure in a second trench extending in the first horizontal direction on the second side of the first active pattern, and includes a first insulating layer on side walls and a bottom surface of the second trench, and a second insulating layer in the second trench on the first insulating layer, a gate-cut extending in the first horizontal direction on the first insulating structure, and a gate electrode extending in the second horizontal direction on the first active pattern.