Fin Isolation Layer Width Variation for Transistor Reliability
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Solution Overview
Problem
Current semiconductor devices face challenges in achieving reliable isolation between transistors, which affects the density and performance of integrated circuit devices, particularly due to limitations in scaling techniques and the presence of short channel effects.
Innovation Solution
The semiconductor device incorporates a fin structure with isolation layers and spacers of varying widths and materials, including nitride and oxide layers, to enhance isolation and gap-fill capabilities, thereby improving transistor reliability and performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional isolation structures are used between transistors, then manufacturing is simpler, but isolation reliability deteriorates due to scaling limitations and short channel effects
Solution Approach 1:
The isolation structure is divided into multiple discrete layers: a first isolation layer (nitride) and a second isolation layer (oxide), each with distinct widths and positions. This segmentation allows each layer to perform specific isolation functions, improving overall isolation reliability while managing complexity through modular design
Solution Approach 2:
Different regions of the isolation structure have different properties: the first isolation layer has a first width extending beyond the fin, while the second isolation layer has a second width that is narrower. This local differentiation optimizes isolation effectiveness at critical interfaces while maintaining structural integrity
2Reliability
If isolation layers are added to improve transistor isolation, then isolation reliability improves, but manufacturing precision requirements worsen due to multiple layer width specifications
Solution Approach 1:
The first isolation layer (nitride) is formed first with a wider dimension that extends beyond the fin structure. This preliminary wider layer provides a foundation that simplifies the subsequent formation of the second isolation layer, as the narrower second layer can be precisely positioned relative to the already-formed first layer, reducing cumulative precision requirements
Solution Approach 2:
The first isolation layer acts as an intermediary structure between the fin and the second isolation layer. Its wider configuration provides a buffer zone that facilitates precise positioning of the second isolation layer while maintaining isolation effectiveness, thereby reducing the overall manufacturing precision burden
3Reliability
If multiple isolation layers with different widths are used, then gap-fill capabilities improve, but device complexity increases
Solution Approach 1:
The isolation structure utilizes width dimensionality differences between layers: the first isolation layer extends wider than the fin, while the second isolation layer has a narrower width. This width-based dimensional differentiation enables superior gap-fill capabilities by ensuring complete coverage of critical interfaces without requiring additional vertical layers, thus improving reliability while controlling complexity
Data Source
AI summary
Semiconductor devices are provided. A semiconductor device includes a fin protruding from a substrate. Moreover, the semiconductor device includes first and second gate structures on the fin, and an isolation region between the first and second gate structures. The isolation region includes first and second portions having different respective widths. Related methods of forming semiconductor devices are also provided.