Group 5 Metal Compound for ALD Thin Film Deposition
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Solution Overview
Problem
Conventional group 5 metal precursor compounds used in atomic layer deposition (ALD) processes have poor thermal stability and low vapor pressure, making it difficult to form uniform thin films at high temperatures and on uneven surfaces, especially for niobium oxide films.
Innovation Solution
A group 5 metal compound with a cyclopentadiene structure, represented by Chemical Formulas 1 and 2, which is thermally stable and has high volatility, allowing for stable deposition as a liquid in ALD processes, reducing residue and enabling improved step coverage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional group 5 metal precursor compounds (PDMAT, TBTDET, TBTDEN) are used in ALD process, then the deposition can be performed, but the compounds have poor thermal stability and low vapor pressure, making it difficult to form uniform thin films at high temperatures
Solution Approach 1:
The patent changes the chemical structure of the precursor compound by introducing a cyclopentadiene ligand and adjusting the alkyl group substituents (R1-R4) to optimize both thermal stability and vapor pressure. This structural parameter change enables the compound to maintain stability at ALD process temperatures while achieving sufficient volatility for uniform film deposition.
Solution Approach 2:
The patent creates a composite precursor structure combining cyclopentadiene ligands with group 5 metal centers (Nb or Ta) and specific alkyl/aryl substituents. This composite molecular structure achieves a balance between thermal stability from the cyclopentadiene framework and appropriate volatility from the organic substituents, solving the contradiction between reliability and manufacturing precision.
2Ease of manufacture
If solid precursor compounds like PDMAT are used, then the deposition process can be initiated, but the compounds are difficult to supply by sublimating constantly and require complex vaporization systems
Solution Approach 1:
The patent transitions the precursor from solid state (PDMAT) to liquid state by introducing volatile organic substituents. This phase change enables the compound to be supplied through simple liquid injection systems rather than complex sublimation equipment, reducing device complexity while maintaining ease of manufacture.
Solution Approach 2:
The patent employs liquid injection and vaporization techniques similar to pneumatic/hydraulic delivery systems. The liquid precursor can be injected through standard syringe pumps and vaporized in the reaction chamber, replacing complex solid sublimation systems with simpler fluid-based delivery mechanisms.
3Productivity
If conventional precursor compounds are used at high temperatures, then the deposition rate can be increased, but the compounds decompose and leave residue on the substrate
Solution Approach 1:
The patent optimizes the molecular structure parameters (cyclopentadiene ligands, alkyl group types and numbers) to adjust the decomposition temperature and vapor pressure. This allows the compound to remain stable at high deposition temperatures while maintaining sufficient volatility, achieving high productivity without residue formation.
Solution Approach 2:
The patent converts the potential harm of high-temperature decomposition into a benefit by designing a compound that intentionally decomposes in a controlled manner during the deposition process. The cyclopentadiene ligands are designed to release metal centers at the optimal temperature, converting what could be harmful decomposition into a beneficial controlled release mechanism that leaves minimal residue.
4Stability of the object's composition
If the ALD process is performed at lower temperatures to avoid thermal diffusion, then element characteristics are preserved, but the vapor pressure of conventional precursors is insufficient for uniform deposition
Solution Approach 1:
The patent changes the vapor pressure parameter of the precursor by modifying the organic substituents (R1-R4 groups). This allows the compound to achieve sufficient vapor pressure at lower temperatures, enabling uniform film deposition without requiring high temperatures that would cause thermal diffusion and compromise element characteristics.
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 compound enhances the quality of thin films deposited on substrates by maintaining structural stability and reducing residue, expanding the window range of the ALD process for forming high-quality group 5 metal-containing thin films.
Implementation Method 1
a group 5 metal compound-containing thin film is generally formed using a metal organic chemical vapor deposition (MOCVD) or atomic layer deposition (ALD) process
Implementation Method 2
since the ALD process performs a self-limiting reaction, it has excellent step coverage
Implementation Method 3
a direct liquid injection (DLI) device or the like which vaporizes liquid by containing liquid in a cylindrical container, or vaporizes liquid injected at a constant flow rate
Data Source
AI summary
A group 5 metal compound according to an embodiment of the present disclosure is represented by any one of the following <Chemical Formula 1> and <Chemical Formula 2>:In <Chemical Formula 1> and <Chemical Formula 2>,M is any one selected from group 5 metal elements,n is any one selected from an integer of 1 to 5,R1 is any one selected from a linear alkyl group having 3 to 6 carbon atoms and a branched alkyl group having 3 to 6 carbon atoms, andR2 and R3 are each independently any one selected from hydrogen, a linear alkyl group having 1 to 4 carbon atoms, and a branched alkyl group having 1 to 4 carbon atoms.