FinFET Work Function Layer Design for Nanometer Density
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Solution Overview
Problem
The semiconductor industry faces challenges in manufacturing three-dimensional designs, such as FinFETs, due to limitations in gate replacement technologies and material selection for high-k dielectric layers, which affect device performance and density.
Innovation Solution
A method for manufacturing semiconductor devices involving the formation of semiconductor fins, gate stacks, and strain layers, with specific processes like epitaxial growth and chemical mechanical polishing, to enhance carrier mobility and performance, and the use of high-k dielectric materials and metal gate structures to improve device density and performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If gate replacement technologies are used to manufacture FinFETs, then device density can be increased, but device performance and reliability deteriorate due to material selection limitations for high-k dielectric layers
Solution Approach 1:
The gate structure employs a composite material system consisting of a high-k dielectric layer (such as HfO2, Al2O3, or Ta2O5) combined with a metal gate electrode layer (such as TiN, TaN, or WN). This composite structure enables simultaneous achievement of high device density through effective gate control and high device performance through optimized electrical characteristics and reliability
Solution Approach 2:
The invention utilizes parameter changes by selecting dielectric materials with high dielectric constants (k > 7) to increase gate control efficiency without increasing physical gate capacitance. This allows higher device density while maintaining performance through adjusted dielectric constant and thickness parameters
2Ease of manufacture
If conventional manufacturing processes are used, then fabrication simplicity is maintained, but manufacturing precision and device performance deteriorate at nanometer technology nodes
Solution Approach 1:
The gate structure is segmented into multiple functional layers: a high-k dielectric layer for electrical performance and a metal gate electrode layer for work function control and reliability. This segmentation allows each layer to be optimized independently while maintaining overall fabrication feasibility through established semiconductor manufacturing processes
Solution Approach 2:
The invention transitions from planar gate structures to three-dimensional FinFET structures with vertical fins extending from the substrate. This dimensional change enables superior gate control over the channel while maintaining compatibility with conventional lithography and deposition processes through adapted fabrication sequences
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 enables the fabrication of high-performance FinFETs with enhanced carrier mobility and density, allowing for improved device performance and efficiency in nanometer technology process nodes.
Implementation Method 1
An epitaxial layer is formed over the substrate
Implementation Method 2
chemical mechanical polishing
Data Source
AI summary
Provided is a semiconductor device including a first fin-type field effect transistor (FinFET). The first FinFET includes a first gate structure over a first semiconductor fin and the first gate structure includes a first work function layer. The first work function layer includes a first layer and a second layer. The first layer has a bar-shaped structure, the second layer has a U-shaped structure encapsulating sidewalls and a bottom surface of the first layer, and the first layer and the second layer include different materials. A method of manufacturing the semiconductor device is also provided.