Multilayered High-k Dielectric Stack for Gate Leakage Control
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Solution Overview
Problem
The increasing density of integrated circuits (ICs) leads to complexity in processing semiconductor devices with decreased feature sizes, particularly due to challenges in forming high-k dielectric layers that maintain optimal thickness and prevent gate leakage current.
Innovation Solution
A multilayered high-k dielectric stack comprising alternating layers of Y2O3 and Al2O3, formed using atomic layer deposition (ALD) with precise thickness control, is employed to enhance the dielectric constant and prevent gate leakage, with optional annealing to achieve inter-diffusion and uniform dielectric properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the thickness of high-k dielectric layer is decreased to increase IC density, then the IC density is improved, but gate leakage current increases
Solution Approach 1:
The patent employs a composite dielectric structure consisting of multiple high-k dielectric layers with different dielectric constants. Specifically, it uses a first high-k dielectric layer with a dielectric constant of 5-10 and a second high-k dielectric layer with a dielectric constant of 10-20, creating a composite material system that optimizes both electrical performance and physical thickness constraints for high-density IC devices.
Solution Approach 2:
The dielectric stack is segmented into multiple distinct high-k dielectric layers rather than using a single uniform layer. This segmentation allows each layer to contribute differently to the overall electrical characteristics, with the total equivalent oxide thickness (EOT) being the sum of individual layer EOTs, thereby enabling precise control over gate leakage while maintaining high IC density.
2Productivity
If aggressive design rules are implemented to increase IC density, then the IC density is improved, but processing complexity increases
Solution Approach 1:
The patent changes the dielectric parameters by introducing multiple high-k dielectric layers with specifically controlled dielectric constants and thicknesses. This parameter optimization allows achieving the desired equivalent oxide thickness (EOT) and electrical performance without requiring proportionally smaller physical dimensions, thereby reducing processing complexity associated with aggressive design rules.
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 improves the dielectric constant of the high-k dielectric stack, reducing gate leakage and enhancing the performance of semiconductor devices by maintaining optimal thickness and inter-diffusion, thus addressing the complexity of smaller feature sizes.
Implementation Method 1
formed using atomic layer deposition (ALD) with precise thickness control
Implementation Method 2
with optional annealing to achieve inter-diffusion and uniform dielectric properties
Data Source
AI summary
A semiconductor device includes a semiconductor substrate, a gate structure, and source/drain regions. The gate structure comprises an yttrium oxide layer over the semiconductor substrate, an aluminum oxide layer over the yttrium oxide layer, and a gate electrode on the aluminum oxide layer. The source/drain regions are on the semiconductor substrate and on opposite sides of the gate structure.