Gate-All-Around Transistor Dielectric Layout for Lower Parasitic Capacitance
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Solution Overview
Problem
Conventional planar MOSFETs and FinFETs face challenges with large leakage current and power consumption due to size effects and structural limitations, while existing gate-all-around transistors have complex manufacturing processes and high parasitic capacitance.
Innovation Solution
A gate-all-around transistor design with a first dielectric layer of high dielectric constant and a second dielectric layer of low dielectric constant, along with a stacked gate structure, to enhance process stability and reduce parasitic capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional planar MOSFET structure is used, then the manufacturing process is simple, but leakage current and power consumption increase due to size effects
Solution Approach 1:
The patent transitions from a planar 2D channel structure to a 3D gate-all-around structure where the gate completely surrounds the channel in three dimensions. This dimensional change enables superior electrostatic control and reduced leakage current while maintaining manufacturing feasibility through established semiconductor processing techniques.
Solution Approach 2:
The patent employs a composite dielectric structure with a first dielectric layer of high dielectric constant and a second dielectric layer of low dielectric constant. This composite material approach optimizes both electrical performance (reducing parasitic capacitance) and process stability in the gate-all-around transistor structure.
2Loss of energy
If a FinFET structure is used, then leakage current is reduced compared to planar MOSFET, but the structure reaches physical limits and performance deteriorates at smaller nodes
Solution Approach 1:
The patent advances from the FinFET's partial gate wraparound to a complete gate-all-around structure that fully encloses the channel in three dimensions. This additional dimensional control provides superior electrostatics and carrier transport efficiency, enabling continued scaling to 3 nm and below where FinFET performance deteriorates.
3Reliability
If a gate-all-around structure is used, then gate control performance and carrier transport efficiency improve, but parasitic capacitance increases
Solution Approach 1:
The patent applies different dielectric constants to different regions: a high dielectric constant material in the first dielectric layer for optimal gate control and channel interaction, and a low dielectric constant material in the second dielectric layer to minimize parasitic capacitance. This local quality differentiation resolves the contradiction between control performance and parasitic effects.
Solution Approach 2:
The patent employs a composite dielectric structure with a first dielectric layer of high dielectric constant and a second dielectric layer of low dielectric constant. This composite material approach optimizes both electrical performance (reducing parasitic capacitance) and process stability in the gate-all-around transistor structure.
4Stability of the object's composition
If dielectric layers with high dielectric constant are used for process stability, then manufacturing stability improves, but parasitic capacitance increases
Solution Approach 1:
The patent applies different dielectric constants to different regions: a high dielectric constant material in the first dielectric layer for optimal gate control and channel interaction, and a low dielectric constant material in the second dielectric layer to minimize parasitic capacitance. This local quality differentiation resolves the contradiction between control performance and parasitic effects.
Solution Approach 2:
The patent employs a composite dielectric structure with a first dielectric layer of high dielectric constant and a second dielectric layer of low dielectric constant. This composite material approach optimizes both electrical performance (reducing parasitic capacitance) and process stability in the gate-all-around transistor structure.
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 design reduces parasitic capacitance and maintains process stability, improving performance and reducing static power consumption, enabling smaller transistor sizes and faster circuit operation.
Implementation Method 1
a dielectric constant of the first dielectric layer is greater than a dielectric constant of the second dielectric layer
Data Source
AI summary
A gate-all-around transistor, comprising: a semiconductor substrate, where a fin-shaped protrusion is provided at a surface of the semiconductor substrate on one side; a source and a drain arranged on the top surface of the fin-shaped protrusion, respectively; a gate comprising a first gate part on the top surface of the fin-shaped protrusion between the source and the drain and a second gate part on a surface of the first gate part on the side away from the fin-shaped protrusion; a first dielectric layer on two opposite sides of the first gate part in a first direction; a second dielectric layer on two opposite sides of the second gate part in the first direction; where: the first direction is parallel to the direction of connecting the source and the drain; a dielectric constant of the first dielectric layer is greater than that of the second dielectric layer.