Nanosheet Gate Isolation Structure for Selective Etch Fabrication
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Solution Overview
Problem
The semiconductor industry faces challenges in improving processing and manufacturing efficiency as ICs become more complex and geometrically smaller, requiring innovative methods to enhance production efficiency and reduce costs while maintaining performance.
Innovation Solution
The method involves forming a stack of semiconductor layers with alternating first and second layers of different etch selectivity, using epitaxial growth processes, and employing advanced patterning and etching techniques to create nanosheet transistors with precise gate and isolation structures, including the formation of sacrificial layers and dielectric features to optimize device architecture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If geometry size is decreased to increase functional density, then production efficiency and cost are improved, but processing complexity increases
Solution Approach 1:
The patent segments the semiconductor structure into alternating first and second semiconductor layers with different etch selectivities, allowing independent processing and isolation of conductive features. This segmentation enables complex devices to be manufactured through modular processing steps, addressing the contradiction between miniaturization benefits and processing complexity.
Solution Approach 2:
The patent introduces an isolation layer as an intermediary element between conductive features and gate electrode layers. This isolation layer mediates the interaction between different device components, enabling precise control during processing while maintaining the benefits of scaled geometry, thus reducing processing complexity despite size reduction.
2Productivity
If functional density is increased by scaling down, then more circuits per chip area are achieved, but manufacturing precision requirements increase
Solution Approach 1:
The patent applies local quality by giving different etch selectivities to different semiconductor layers (first vs. second layers). This allows selective processing of specific regions with different precision requirements, enabling high functional density while maintaining manufacturability through localized material property differentiation.
Solution Approach 2:
The patent changes material parameters by selecting semiconductor layers with different etch selectivities, allowing precise control over which layers are processed at each step. This parameter differentiation enables manufacturing of high-density circuits with appropriate precision control for each specific geometric feature.
3Reliability
If advanced patterning and etching techniques are used to create nanosheet transistors, then device performance is improved, but process complexity increases
Solution Approach 1:
The patent performs preliminary actions by pre-forming the alternating semiconductor layer stack with different etch selectivities before final device fabrication. This preliminary structuring enables subsequent simple selective etching processes to create complex nanosheet transistor architectures, improving device performance while actually simplifying the overall process complexity.
Solution Approach 2:
The patent transitions from planar processing to three-dimensional nanosheet structures by utilizing vertical stacking of alternating semiconductor layers. This dimensional change enables advanced device performance through improved carrier confinement and control, while the self-aligned nature of the stacked structure reduces the complexity of patterning processes.
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 creation of complex nanosheet transistors with improved performance and manufacturing efficiency, reducing costs and enhancing production capabilities by leveraging advanced materials and processes.
Implementation Method 1
forming a stack of semiconductor layers with alternating first and second layers of different etch selectivity, using epitaxial growth processes
Data Source
AI summary
A semiconductor device structure, along with methods of forming such, are described. The structure includes first and second dielectric features and a first semiconductor layer disposed between the first and second dielectric features. The structure further includes an isolation layer disposed between the first and second dielectric features, and the isolation layer is in contact with the first and second dielectric features. The first semiconductor layer is disposed over the isolation layer. The structure further includes a gate dielectric layer disposed over the isolation layer and a gate electrode layer disposed over the gate dielectric layer. The gate electrode layer has an end extending to a level between a first plane defined by a first surface of the first semiconductor layer and a second plane defined by a second surface opposite the first surface.