FinFET Gate Dielectric Features for Lower Gate-Drain Capacitance
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Solution Overview
Problem
The semiconductor industry faces challenges in improving processing and manufacturing efficiency as the complexity of semiconductor integrated circuits (ICs) increases with scaling down, requiring innovative methods to enhance device density and reduce manufacturing costs.
Innovation Solution
The method involves forming a semiconductor device structure with a stack of semiconductor layers, including alternating first and second layers with different etch selectivity, and using a dielectric feature with a high-K and low-K dielectric liner to create a nanosheet transistor structure, which increases device density and reduces gate drain capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional planar transistor structures are used, then manufacturing processes are simpler, but device density and performance are limited
Solution Approach 1:
The patent transitions from planar 2D channel structures to three-dimensional FinFET structures with vertical fins extending from the substrate. This dimensional change increases the effective channel area and device density while maintaining manufacturability through established etching and deposition processes adapted for vertical geometries.
Solution Approach 2:
The transistor channel is segmented into multiple vertical fins rather than a single planar region. Each fin acts as an independent current path, allowing the device to achieve higher density by packing multiple channels in a compact footprint while using standard semiconductor fabrication techniques.
2Productivity
If gate electrode layers are placed close together to increase density, then device density improves, but gate drain capacitance increases reducing speed
Solution Approach 1:
A dielectric feature is introduced as an intermediary element positioned between adjacent gate electrode layers. This dielectric layer acts as an electrical insulator that reduces parasitic capacitance coupling between gates while maintaining physical proximity for high density. The dielectric material with appropriate K-value is selected to optimize the balance between electrical isolation and space efficiency.
3Productivity
If advanced nanosheet transistor structures are implemented to increase density, then device density and speed improve, but manufacturing complexity and costs increase
Solution Approach 1:
The nanosheet transistor structure employs nested layers where alternating semiconductor and dielectric layers are stacked vertically to form multiple channel sheets. Each layer is formed using conformal deposition techniques that naturally create the nested configuration. This approach achieves high density by utilizing the vertical dimension while relying on self-aligned processes that reduce manufacturing complexity.
Solution Approach 2:
Dielectric features and liner layers are formed in advance before final gate electrode deposition. This preliminary formation of the dielectric infrastructure establishes the electrical isolation framework early in the process, enabling subsequent gate layers to be deposited with precise alignment and reducing the need for complex post-processing steps.
Data Source
AI summary
A semiconductor device structure, along with methods of forming such, are described. The structure includes a first and second gate electrode layers, and a dielectric feature disposed between the first and second gate electrode layers. The dielectric feature has a first surface. The structure further includes a first conductive layer disposed on the first gate electrode layer. The first conductive layer has a second surface. The structure further includes a second conductive layer disposed on the second gate electrode layer. The second conductive layer has a third surface, and the first, second, and third surfaces are coplanar. The structure further includes a third conductive layer disposed over the first conductive layer, a fourth conductive layer disposed over the second conductive layer, and a dielectric layer disposed on the first surface of the dielectric feature. The dielectric layer is disposed between the third conductive layer and the fourth conductive layer.