Multi-Layer Dielectric Spacer for Semiconductor FinFET
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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, leading to issues with device reliability and performance.
Innovation Solution
A semiconductor device structure is formed using fin structures with a multi-layer dielectric spacer element comprising a high-K dielectric material and a low-K dielectric material, which reduces parasitic capacitances and improves device performance by enhancing carrier mobility and reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If feature sizes continue to decrease to increase functional density, then production efficiency increases and costs decrease, but fabrication process complexity and difficulty increase
Solution Approach 1:
The fabrication process is divided into multiple sequential stages including forming first and second trenches at different depths, selective epitaxial growth in specific regions, and staged doping processes. This segmentation allows complex operations to be broken down into manageable steps that can be performed with existing fabrication equipment and techniques.
Solution Approach 2:
Different regions of the semiconductor structure are given different properties through selective epitaxial growth where semiconductor material is grown only in specific trench regions, and selective doping where impurity layers are formed in particular areas. This local differentiation enables complex device functionality while using standard fabrication processes.
2Productivity
If feature sizes continue to decrease, then functional density increases, but device reliability deteriorates
Solution Approach 1:
Isolation layers are formed beforehand to electrically isolate adjacent semiconductor structures from each other, preventing unwanted interactions that could compromise device reliability. These isolation regions are created during the epitaxial growth process to ensure proper electrical separation before subsequent doping and fabrication steps.
Solution Approach 2:
Impurity layers are introduced as intermediary elements between semiconductor regions to control electrical properties and create proper junctions. These doped regions serve as mediators that enable reliable electrical connections and isolation between different device components at scaled dimensions.
3Ease of manufacture
If single-layer dielectric spacers are used, then manufacturing is simple, but parasitic capacitances are high
Solution Approach 1:
The dielectric spacer structure uses multiple layers with different dielectric constants - a first dielectric layer with higher permittivity and a second dielectric layer with lower permittivity. This composite structure reduces parasitic capacitances between adjacent semiconductor structures while maintaining mechanical integrity and manufacturability through sequential deposition processes.
Solution Approach 2:
The dielectric constant parameter is varied through the use of different materials in different spacer regions. By changing the dielectric constant from high to low across the spacer structure, the parasitic capacitance is reduced while the spacer maintains its structural function. This parameter optimization is achieved through selective material deposition.
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
The use of composite spacer elements with different dielectric constants in the semiconductor device structure effectively lowers parasitic capacitances, enhances device performance, and improves reliability by reducing resistance and power consumption.
Implementation Method 1
a multi-layer dielectric spacer element comprising a high-K dielectric material and a low-K dielectric material, which reduces parasitic capacitances
Data Source
AI summary
Structures and formation methods of a semiconductor device structure are provided. The semiconductor device structure includes a fin structure over a semiconductor substrate. The semiconductor device structure also includes a gate stack covering a portion of the fin structure. The semiconductor device structure further includes a spacer element over a sidewall of the gate stack. The spacer element includes a first layer and a second layer over the first layer. The dielectric constant of the first layer is greater than the dielectric constant of the second layer. A gate dielectric layer of the gate stack adjoins the first layer and the second layer.