Low-k Gate-End Dielectric Layout for CFET Capacitance Reduction
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Solution Overview
Problem
In stacked complementary field-effect transistors (CFETs), maintaining minimum spacing between CMG regions while scaling active area layers results in longer gate ends, leading to increased gate end capacitance.
Innovation Solution
Implementing a 2D CMG region with a low-k dielectric material in a second portion that cuts the gates to provide shortened gate ends, reducing capacitance by using a combination of low-k and high-k dielectric materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If active area layers are scaled down to maintain minimum spacing between CMG regions, then device density increases, but gate end capacitance increases due to longer gate ends
Solution Approach 1:
The patent applies local quality by using different dielectric materials (low-k dielectric in the second portion, high-k dielectric in the first portion) at different locations within the CMG region. This allows the gate end capacitance to be reduced locally where it is most problematic (near the gate end) while maintaining other electrical characteristics in different regions.
Solution Approach 2:
The patent uses composite materials by combining low-k dielectric material and high-k dielectric material within the same CMG region. The low-k dielectric reduces capacitance in the critical gate end area, while the high-k dielectric maintains electrical performance in other areas, achieving a balance between reducing gate end capacitance and maintaining device performance.
2Object-generated harmful factors
If gate end length is reduced to minimize capacitance, then gate end capacitance decreases, but manufacturing precision requirements increase
Solution Approach 1:
The patent introduces the CMG region with specific dielectric materials as an intermediary structure between the gate and the active area. This intermediary structure allows for controlled capacitance reduction without requiring extremely precise control of gate end dimensions, as the dielectric materials themselves provide the capacitance management function.
3Object-generated harmful factors
If low-k dielectric material is used in the CMG region, then gate end capacitance is reduced, but dielectric breakdown risk increases
Solution Approach 1:
The patent applies low-k dielectric material specifically in the second portion of the CMG region where capacitance reduction is most needed, while using high-k dielectric material in the first portion where electrical breakdown resistance is critical. This local differentiation allows capacitance reduction without compromising overall reliability.
Solution Approach 2:
The patent creates a composite dielectric structure combining low-k and high-k dielectric materials in the CMG region. The low-k portion reduces capacitance while the high-k portion provides electrical breakdown resistance, achieving both objectives simultaneously through material composition.
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 solution effectively minimizes gate end capacitance, enhancing the performance of CFETs by reducing the length of gate ends and maintaining efficient cell scaling.
Implementation Method 1
first low-k dielectric material situated in the first dielectric region
Data Source
AI summary
A semiconductor device including a first active area layer that extends in a first direction, a first metal over diffusion layer that extends in a second direction that is different than the first direction, the first metal over diffusion layer situated over the first active area layer, a first gate that extends in the second direction and over the first active area layer, a first gate end of the first gate that abuts a first dielectric region, and first low-k dielectric material situated in the first dielectric region.