FinFET Gate Contact Configuration for SRAM Speed and Area
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Solution Overview
Problem
The semiconductor industry faces challenges in designing SRAM devices that balance data access speed and area efficiency, as existing SRAM devices either prioritize speed or area optimization, but not both simultaneously.
Innovation Solution
The use of Fin Field-effect Transistors (FinFETs) with specific gate contact and barrier layer configurations, including high-K dielectric materials, allows for more flexible placement of gate contacts and improved isolation between gate and source/drain contacts, enhancing data access speed while reducing area occupancy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If SRAM devices are designed to have faster data access, then data access speed is improved, but area occupancy increases
Solution Approach 1:
The patent applies different dielectric materials with different properties to different regions: high-K dielectric material is used specifically in the gate contact region to improve data access speed, while low-K dielectric material is used in the interlayer dielectric region to reduce area occupancy and improve isolation. This local differentiation resolves the contradiction by optimizing each region for its specific function.
Solution Approach 2:
The patent uses a composite dielectric structure combining high-K dielectric material (such as hafnium oxide, tantalum oxide) and low-K dielectric material (such as silicon oxide, fluorinated silicon oxide) in different layers and regions. This composite approach allows the gate contact region to benefit from high-K materials for speed while the overall structure maintains compact area through low-K materials for isolation.
2Reliability
If barrier layer is added around gate contact, then isolation between gate and source/drain contacts is improved, but device complexity increases
Solution Approach 1:
The patent merges the barrier layer function with the interlayer dielectric structure by forming the barrier layer as an integrated part of the dielectric stack. The low-K dielectric material serves both as the interlayer dielectric and as the barrier providing isolation, eliminating the need for separate barrier structures and reducing overall device complexity.
Solution Approach 2:
The low-K dielectric material performs multiple functions simultaneously: it acts as the interlayer dielectric for electrical isolation, serves as a barrier layer to prevent diffusion between gate and source/drain contacts, and provides mechanical support. This multi-functionality reduces the number of separate components needed.
Data Source
AI summary
A semiconductor device includes a substrate, a semiconductor fin, first and second source/drains, a gate electrode, and a gate contact. The semiconductor fin is disposed on the substrate. The first and second source/drains is disposed on the semiconductor fin. The gate electrode is across the semiconductor fin and exposes the first and second source/drains. The gate contact is disposed on the gate electrode and has an elliptical profile with a major axis extending along a lengthwise direction of the gate electrode when viewed from above the gate contact.