Nitrogen-Containing Interface Layer for High-k Dielectric Oxygen Vacancy Reduction
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Solution Overview
Problem
Existing semiconductor structures face challenges with large leakage currents and dielectric relaxation issues due to defects in high-k dielectric materials, particularly oxygen vacancies, which affect electrical performance and stability under bias temperature conditions.
Innovation Solution
A method involving a nitrogen-containing environment for annealing processes to form a nitrogen-containing layer, which reduces the density of active oxygen vacancies in the high-k dielectric layer by allowing nitrogen ions to diffuse into the layer, thereby improving the compactness and dielectric properties, and forming a gate electrode layer on top.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If high-k dielectric material is used to replace traditional SiO2 dielectric material, then leakage current is reduced, but dielectric relaxation current increases due to oxygen vacancies in high-k material
Solution Approach 1:
A nitrogen-containing layer is introduced as an intermediary between the substrate and the high-k dielectric layer. This intermediate layer serves as a buffer that prevents direct interaction between the high-k material and the substrate, thereby reducing oxygen vacancies and dielectric relaxation current while maintaining the low leakage current benefit of high-k materials
Solution Approach 2:
The patent changes the chemical composition parameter of the interface layer by introducing nitrogen-containing species through annealing processes. This parameter change transforms the interface layer into a nitrogen-containing layer that can effectively passivate oxygen vacancies in the high-k dielectric layer, thereby reducing dielectric relaxation current
2Productivity
If gate dielectric layer thickness is decreased to continue scaling, then transistor performance improves, but leakage current increases due to approaching physical limits
Solution Approach 1:
The patent employs a composite gate dielectric structure consisting of multiple layers: a substrate, an interface layer, a nitrogen-containing layer, and a high-k dielectric layer. This composite structure allows the system to achieve both thin effective thickness for high performance and controlled material properties to minimize leakage current
Solution Approach 2:
The patent applies local quality enhancement by creating a nitrogen-containing layer with specific chemical properties at the critical interface region. This localized modification addresses the leakage issue at the interface without requiring the entire gate dielectric to be thicker, thus maintaining overall device performance
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 effectively reduces the dielectric relaxation current, suppresses positive and negative bias temperature instability characteristics, and enhances the overall electrical performance of semiconductor structures by minimizing oxygen vacancies in the high-k dielectric layer.
Implementation Method 1
performing a second annealing process on the high-k dielectric layer to allow nitrogen ions in the nitrogen-containing layer to diffuse into the high-k dielectric layer to reduce a density of active oxygen vacancies in the high-k dielectric layer
Implementation Method 2
performing a first annealing process on the interface layer under a nitrogen-containing environment to form a nitrogen-containing layer from a top portion of the interface layer. The first annealing process also deactivates non-bonded silicon ions and oxygen ions in the interface layer
Data Source
AI summary
A method for fabricating a semiconductor structure includes providing a substrate, forming an interface layer on the substrate, and then performing a first annealing process on the interface layer under a nitrogen-containing environment to form a nitrogen-containing layer from a top portion of the interface layer. The first annealing process also deactivates non-bonded silicon ions and oxygen ions in the interface layer. The method further includes forming a high-k dielectric layer on the nitrogen-containing layer, and performing a second annealing process on the high-k dielectric layer to allow nitrogen ions in the nitrogen-containing layer to diffuse into the high-k dielectric layer to reduce a density of active oxygen vacancies in the high-k dielectric layer. Finally, the method includes forming a gate electrode layer on the high-k dielectric layer.