Gate Dielectric Passivation Through Work Function Layer Soaking
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Solution Overview
Problem
As semiconductor devices continue to integrate more components into a given area through reduced feature sizes, issues such as electrical trapping defects in gate dielectric layers become prevalent, necessitating improved passivation methods.
Innovation Solution
Introduce a passivation dopant, such as fluorine, into the gate dielectric layer through a work function layer using a soaking process to passivate electrical trapping defects, ensuring minimal material degradation and conformal implantation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional lithography and deposition methods are used to reduce minimum feature size for higher integration density, then more components can be integrated into a given area, but electrical trapping defects in gate dielectric layers become prevalent
Solution Approach 1:
The patent applies preliminary action by performing a soaking process with a fluorine-containing precursor on the gate dielectric layer before subsequent manufacturing steps. This pre-treatment introduces fluorine atoms that passivate electrical trapping defects in advance, preventing reliability issues before they affect device performance or require rework.
Solution Approach 2:
The patent uses fluorine atoms as an intermediary substance that mediates between the gate dielectric layer and electrical trapping defects. The fluorine-containing precursor serves as a carrier that delivers fluorine atoms to the dielectric layer, where they bond to silicon atoms and passivate defects without directly contacting or damaging other device structures.
2Reliability
If dopant implantation is performed to passivate defects in the dielectric layer, then electrical trapping defects are reduced, but material degradation and damage occur during implantation
Solution Approach 1:
The patent replaces the mechanical implantation process with a chemical deposition approach. Instead of physically bombarding the dielectric layer with dopant ions through high-energy implantation, the patent uses a fluorine-containing precursor that chemically deposits fluorine atoms onto the gate dielectric layer at lower energies, achieving passivation without mechanical damage.
Solution Approach 2:
The patent changes the physical and chemical parameters of the dopant introduction process. By using a fluorine-containing precursor in a deposition process rather than traditional ion implantation, the patent operates at lower energies and temperatures, altering the interaction mechanism from high-energy collision to low-energy chemical bonding, thereby preserving material integrity while achieving passivation.
3Reliability
If traditional doping methods are used to passivate defects, then some defect reduction is achieved, but process control is limited and manufacturing window is reduced
Solution Approach 1:
The patent changes the process parameters from high-energy ion implantation to low-energy chemical deposition. This allows for better process control through standard deposition techniques, enabling precise control of fluorine incorporation levels and achieving a larger manufacturing window with less sensitivity to process variations.
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 method effectively passivates defects in the dielectric layer, maintaining the integrity of the work function layer and enhancing process control, allowing for a larger manufacturing window and reduced damage during implantation.
Implementation Method 1
conformally diffusing fluorine into an interfacial oxide through the high-k dielectric and through the first work function metal by soaking the first work function metal in nitrogen trifluoride
Data Source
AI summary
Semiconductor devices and methods which utilize a passivation dopant to passivate a gate dielectric layer are provided. The passivation dopant is introduced to the gate dielectric layer through a work function layer using a process such as a soaking method. The passivation dopant is an atom which may help to passivate electrical trapping defects, such as fluorine.