Gate Dielectric Fluorine Treatment After Work Function Metal Deposition
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
As semiconductor devices continue to scale down, imperfections in the gate dielectric, such as amorphous grains in high-k dielectrics, lead to gate leakage and reliability issues, which degrade transistor performance and can cause failures.
Innovation Solution
Introduce fluorine to the high-k dielectric after the deposition of work function metal layers, using fluorine treatment and energy boosting processes to improve bond stability and reduce current leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fluorine is introduced before work function metal deposition, then gate dielectric quality improves, but fluorine escapes during subsequent thermal processes
Solution Approach 1:
The patent applies preliminary action by introducing fluorine to the gate dielectric AFTER work function metal deposition rather than before. This sequencing ensures that the fluorine treatment occurs on a stable, already-formed dielectric layer, preventing fluorine escape during subsequent thermal processes while still achieving the desired defect passivation effect.
2Productivity
If gate size is scaled down, then production efficiency increases, but gate leakage problems worsen
Solution Approach 1:
The patent applies parameter changes by modifying the chemical composition of the gate dielectric through fluorine introduction. This changes the electrical properties of the dielectric material, specifically reducing gate leakage current by passivating defects and amorphous grains in the high-k dielectric, thereby maintaining reliability at scaled dimensions.
3Ease of manufacture
If amorphous grains are present in high-k dielectric, then dielectric formation is simplified, but gate leakage increases
Solution Approach 1:
The patent converts the harmful effect of amorphous grains and defects in the high-k dielectric into a benefit by introducing fluorine that specifically targets and passivates these imperfections. Rather than requiring a perfectly crystalline dielectric, the fluorine treatment transforms the defective structure into a functional, low-leakage gate dielectric.
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
Enhances device performance and reliability by plugging traps in the amorphous grains of the high-k dielectric, ensuring fluorine does not escape during subsequent thermal processes, thereby improving the quality of the gate dielectric.
Implementation Method 1
One or more processes are performed to cause fluorine from the fluorine-containing material to diffuse at least partially into the gate dielectric structure
Implementation Method 2
using fluorine treatment and energy boosting processes to improve bond stability
Data Source
AI summary
A gate dielectric structure is formed over a channel structure. One or more work function (WF) metal layers of a metal gate are formed over the gate dielectric structure. The one or more WF metal layers are treated with a fluorine-containing material. One or more processes are performed to cause fluorine from the fluorine-containing material to diffuse at least partially into the gate dielectric structure.