Backside Contact Spacer Structure for Source/Drain Isolation
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Solution Overview
Problem
Existing integrated circuit devices face challenges in achieving reliable operation due to limitations in transistor structure optimization, particularly in the integration of back side contacts and spacer structures.
Innovation Solution
The integrated circuit device incorporates a back side contact extending through a gap-fill insulating layer, connected to source/drain connection structures, and surrounded by spacer structures to enhance electrical isolation and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a back side contact is extended through the gap-fill insulating layer to connect with source/drain connection structures, then electrical connectivity and device performance are improved, but the risk of unnecessary current flow into the source/drain region increases
Solution Approach 1:
The spacer structure serves as an intermediary insulating element positioned between the back side contact and the source/drain region. This mediator prevents direct electrical contact and unwanted current flow while allowing the back side contact to maintain its electrical connection to the source/drain connection structure, thus resolving the contradiction between improving electrical connectivity and preventing harmful current flow.
2Reliability
If spacer structures are added around the back side contact to prevent harmful current flow, then device reliability is improved, but device complexity increases
Solution Approach 1:
The spacer structure is formed by merging multiple functional elements: it serves as both an insulating barrier to prevent harmful current flow and as a structural support element. By combining these functions into a single integrated component rather than adding separate elements, the design improves reliability while minimizing the increase in device complexity.
3Reliability
If the back side contact horizontal width at upper portion is made greater than at lower portion, then electrical isolation is enhanced, but manufacturing precision requirements increase
Solution Approach 1:
The back side contact is designed with an asymmetric cross-sectional profile where the horizontal width at the upper portion is intentionally made greater than at the lower portion. This asymmetric geometry enhances electrical isolation by creating a larger insulating barrier area while the gradual transition in width makes the structure more tolerant to manufacturing variations, thus balancing the trade-off between improved isolation and manufacturing precision requirements.
Data Source
AI summary
An integrated circuit device comprises a plurality of device isolation layers extending in a first horizontal direction and spaced apart from each other in a second horizontal direction perpendicular to the first horizontal direction; a gap-fill insulating layer disposed between the plurality of device isolation layers; a plurality of gate lines disposed on the gap-fill insulating layer and extending lengthwise in the second horizontal direction; a plurality of source/drain regions disposed between adjacent gate lines of the plurality of gate lines; a plurality of source/drain connection structures disposed under the plurality of source/drain regions; and first and second spacer structures in contact with upper sidewalls of the back side contact. The first and second spacer structures are disposed between the gap-fill insulating layer and the first source/drain connection structure.