FinFET Gate Dielectric Structure for Scaled Device Reliability
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Solution Overview
Problem
The semiconductor industry faces challenges in forming reliable semiconductor devices at increasingly smaller sizes due to the complexity and difficulty of fabrication processes as feature sizes decrease, affecting production efficiency and costs.
Innovation Solution
The formation of semiconductor device structures using FinFETs, where fins are patterned using photolithography and self-aligned processes, with gate stacks, spacers, stressors, and dielectric layers formed through various deposition and etching processes to improve device reliability and yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If feature sizes continue to decrease to increase functional density, then production efficiency and costs are improved, but fabrication process difficulty and device reliability worsen
Solution Approach 1:
The gate dielectric layer is segmented into multiple layers including a first dielectric layer and a second dielectric layer with different materials and properties. This segmentation allows each layer to perform specific functions - the first layer provides adhesion and interface quality while the second layer provides electrical isolation - thereby maintaining device reliability at scaled dimensions without compromising production efficiency
Solution Approach 2:
Different regions of the gate dielectric structure are assigned different material compositions and thicknesses. The first dielectric layer has specific properties optimized for interface adhesion while the second layer has properties optimized for electrical isolation. This local differentiation enables the structure to meet reliability requirements at smaller feature sizes while maintaining manufacturing efficiency
2Productivity
If feature sizes continue to decrease to increase functional density, then production efficiency and costs are improved, but fabrication process complexity worsens
Solution Approach 1:
The first dielectric layer is formed as a preliminary structure before the second dielectric layer. This preliminary action establishes a stable foundation with proper adhesion properties, simplifying subsequent processing steps and reducing fabrication complexity even as feature sizes decrease and functional density increases
3Productivity
If geometric size decreases to increase functional density, then production efficiency is improved, but manufacturing precision requirements worsen
Solution Approach 1:
The gate dielectric structure uses locally optimized material properties where the first dielectric layer provides superior interface adhesion and the second layer provides electrical isolation. This local quality differentiation maintains manufacturing precision at smaller dimensions by ensuring each region performs its specific function optimally
Solution Approach 2:
The gate dielectric layer is formed as a composite structure with two different dielectric materials. This composite approach allows each material to contribute its superior properties - adhesion for the first layer and isolation for the second layer - thereby maintaining fabrication precision while enabling continued scaling for improved productivity
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enhances the reliability and yield of semiconductor devices by allowing for smaller pitches and improved adhesion and conductivity, addressing the challenges of scaling down in semiconductor manufacturing.
Implementation Method 1
gate dielectric layers are formed over the fin structures
Implementation Method 2
gate dielectric layers are formed over the fin structures
Implementation Method 3
fins are patterned using photolithography
Implementation Method 4
self-aligned processes
Data Source
AI summary
A semiconductor device structure is provided. The semiconductor device structure includes a substrate. The semiconductor device structure includes a gate stack over the substrate. The gate stack includes a first dielectric layer, a work function layer, and a gate electrode sequentially stacked over the substrate, the first dielectric layer has a thin portion and a thick portion, the thin portion is thinner than the thick portion and surrounds the thick portion, and the first dielectric layer is a single-layer structure. The semiconductor device structure includes an insulating layer over the substrate and wrapping around the gate stack. The thin portion is between the thick portion and the insulating layer.