Fluoride Passivation for Chloride-Tolerant Dielectric Deposition
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Solution Overview
Problem
The integration of SrTiO3 and titanium chloride-based metal electrode processes in insulator-metal structures is challenging due to severe reactions, leading to destruction of the insulator-metal interface and structure, as titanium chloride-based chemistry corrodes the dielectric material, ruining the electrical properties of capacitors.
Innovation Solution
The use of titanium fluoride (TiF4) as a precursor instead of titanium chloride, which forms a passivation layer that protects the high-k dielectric layer from chloride, bromide, or iodide attack, allowing for the deposition of titanium nitride electrodes without damaging the SrTiO3 dielectric.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If titanium chloride-based chemistry is used to deposit metal electrodes, then the deposition process can be performed, but the dielectric material is corroded and the insulator-metal interface is destroyed
Solution Approach 1:
A fluoride passivation layer is introduced as an intermediary between the high-k dielectric layer and the titanium chloride-based electrode. This passivation layer acts as a protective barrier that prevents direct contact and harmful chemical reactions between the chloride-based deposition chemistry and the dielectric material, thereby enabling electrode deposition while preserving the insulator-metal interface integrity
Solution Approach 2:
The fluoride passivation layer is formed in advance before the titanium chloride-based electrode deposition process. This preliminary action prepares the surface by creating a protective barrier that will withstand the subsequent harsh chemical environment during electrode formation, preventing corrosion before it can occur
2Reliability
If a passivation layer is formed to protect the high-k dielectric layer, then the dielectric material is protected from corrosion, but an additional process step is required
Solution Approach 1:
The fluoride passivation layer formation is merged with the electrode deposition process by using the same reaction chamber and sequencing the steps within the overall electrode formation workflow. The passivation layer formation becomes an integrated preliminary step rather than a separate, standalone process, thereby reducing overall process complexity while maintaining protection functionality
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
TiF4 enables the successful deposition of titanium nitride electrodes on SrTiO3 without corrosion, maintaining the electrical properties of the capacitors and forming a conductive nitride passivation layer that enhances the work function of the metal layer.
Implementation Method 1
providing a fluorine containing chemical into the reaction chamber in a vapor phase, such that the fluorine containing chemical reacts with the high-k layer to form a passivation layer
Implementation Method 2
providing a pulse of a nitrogen containing vapor phase reactant to the reaction chamber such that the nitrogen containing vapor phase reactant reacts with the titanium fluoride on the substrate to form a titanium nitride containing thin film
Data Source
AI summary
Methods are disclosed herein for depositing a passivation layer comprising fluorine over a dielectric material that is sensitive to chlorine, bromine, and iodine. The passivation layer can protect the sensitive dielectric layer thereby enabling deposition using precursors comprising chlorine, bromine, and iodine over the passivation layer.