Halosilazane Precursors for Low-Temperature High-Purity Si Films
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Solution Overview
Problem
Current methods for preparing halogenated silicon-nitrogen compounds, such as trisilylamine, face challenges with low selectivity and yield due to the cleavage of Si-N bonds and formation of side products, limiting their commercial application in vapor-based deposition processes for semiconductor and photovoltaic manufacturing.
Innovation Solution
The development of Si-containing film forming compositions comprising halosilazane or halogenated hydrosilazane precursors with specific formulas, allowing for selective halogenation to produce high-purity monohalogenated derivatives using trityl halides as halogenation reagents and catalysts like BPh3 or Pd, which avoid strong electro- or nucleophilic interactions and acid formation, enabling efficient deposition of silicon-containing films.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional methods are used to prepare halogenated silicon-nitrogen compounds, then deposition processes can be performed, but selectivity and yield are low due to Si-N bond cleavage and side product formation
Solution Approach 1:
The patent changes the chemical parameters of the precursor molecules by introducing specific halogenated silazane structures with controlled Si-H and Si-X bonds. This molecular design allows the deposition process to proceed at lower temperatures while maintaining high film purity and reducing unwanted side reactions that would otherwise cleave Si-N bonds
Solution Approach 2:
The patent uses carefully designed halogenated silazane intermediaries that act as stable precursors. These intermediary compounds facilitate the deposition process by providing a controlled release mechanism for silicon, nitrogen, and halogen atoms during thermal decomposition, thereby avoiding direct Si-N bond cleavage and improving both yield and film purity
2Temperature
If low temperature deposition is used to protect organic films on substrates, then substrate damage is avoided, but deposition rate becomes unacceptably slow
Solution Approach 1:
The patent modifies the thermal stability parameters of the precursor molecules through halogenation. The introduced Si-X bonds (where X is halogen) have specific bond energies that enable controlled decomposition at lower temperatures (20-100°C) while maintaining adequate deposition rates through optimized molecular structure and reactivity
Solution Approach 2:
The patent employs periodic pulse deposition techniques where precursors are introduced in controlled pulses followed by thermal treatment cycles. This periodic action allows accumulation of sufficient material for acceptable deposition rates while keeping peak temperatures low enough to protect organic films on substrates
3Adaptability or versatility
If trisilylamine is used as a low temperature silicon nitride precursor, then versatility is improved, but applicability to thermal ALD is limited requiring plasma activation
Solution Approach 1:
The patent modifies the chemical parameters of trisilylamine by introducing halogen substituents on silicon atoms. This creates derivatives with tuned reactivity and thermal stability that enable the materials to function in thermal ALD processes without requiring plasma activation, thus simplifying the overall process complexity while maintaining versatility
Solution Approach 2:
The patent performs preliminary chemical modification of the trisilylamine structure through halogenation before the deposition process. This preliminary action pre-configures the precursor molecules with optimal bond energies and reactivity characteristics that enable direct thermal decomposition in ALD cycles, eliminating the need for subsequent plasma activation steps
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 achieves high selectivity and yield in the production of halogenated silicon-nitrogen compounds, suitable for industrial-scale use in CVD and ALD processes, providing high-purity silicon oxide, nitride, and oxinitride films with improved deposition rates and film quality.
Implementation Method 1
depositing at least part of the halosilazane or halogenated hydrosilazane precursor onto the substrate to form the silicon-containing film on the substrate using a vapor deposition process
Implementation Method 2
introducing a vapor comprising the halosilazane or halogenated hydrosilazane precursor into a reactor having a substrate disposed therein and depositing at least part of the halosilazane or halogenated hydrosilazane precursor onto the substrate
Data Source
AI summary
Methods for producing halosilazane comprise halogenating a hydrosilazane with a halogenating agent to produce the halosilazane, the halosilazane having a formula(SiHa(NR2)bXc)(n+2)Nn(SiH(2−d)Xd)(n−1),wherein each a, b, c is independently 0 to 3; a+b+c=3; d is 0 to 2 and n≥1; wherein X is selected from a halogen atom selected from F, Cl, Br or I; each R is selected from H, a C1-C6 linear or branched, saturated or unsaturated hydrocarbyl group, or a silyl group [SiR′3]; further wherein each R′ of the [SiR′3] is independently selected from H, a halogen atom selected from F, Cl, Br or I, a C1-C4 saturated or unsaturated hydrocarbyl group, a C1-C4 saturated or unsaturated alkoxy group, or an amino group [—NR1R2] with each R1 and R2 being further selected from H or a C1-C6 linear or branched, saturated or unsaturated hydrocarbyl group, provided that when c=0, d≠0; or d=0, c≠0.