Electron-withdrawing functional groups on si-chalcogen precursors
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Solution Overview
Problem
Current deposition techniques for silicon nitride and silicon oxide films face challenges with limited availability of precursors that have robust thermal stability, high reactivity, and vapor pressure, leading to halogen contamination and the need for high-temperature processes, which are undesirable for temperature-sensitive substrates.
Innovation Solution
The use of silicon-chalcogen precursors containing an electron withdrawing group, which are halogen-free, allowing for the deposition of silicon nitride, silicon oxide, and silicon oxynitride films through atomic layer deposition or chemical vapor deposition at lower temperatures, ensuring thermal stability and reduced halogen content.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If halogen-containing silane precursors are used for deposition, then film formation occurs, but halogen contamination occurs in the deposited films
Solution Approach 1:
The patent removes halogen atoms from the precursor molecule structure, replacing them with electron-withdrawing groups (such as -CF3, -OCF3, -SO2CF3) attached to alkyl chains. This extraction of the harmful halogen element while retaining the necessary reactivity for film deposition directly resolves the contamination issue.
Solution Approach 2:
The patent changes the chemical composition parameters of the precursor by introducing electron-withdrawing groups with specific electronegativity values and bond characteristics. These parameter changes modify the precursor's thermal stability and reactivity, enabling low-temperature deposition without halogen contamination.
2Productivity
If conventional precursors are used, then deposition can proceed, but high temperature processes are required which are undesirable for temperature-sensitive substrates
Solution Approach 1:
The patent modifies the thermal parameters of the precursor by incorporating electron-withdrawing groups that stabilize the Si-chalcogen bond. This allows the deposition reaction to proceed at lower temperatures (below 400°C) while maintaining adequate reaction kinetics and film quality.
Solution Approach 2:
The patent creates a composite precursor structure combining silicon, chalcogen (S, Se, or Te), and electron-withdrawing groups (such as trifluoromethylsulfonate). This composite molecular structure provides both the necessary reactivity for deposition and thermal stability for low-temperature processing.
3Reliability
If precursors with robust thermal stability and high reactivity are required, then limited number of viable precursors are available
Solution Approach 1:
The patent develops a universal precursor platform based on Si-chalcogen cores with various electron-withdrawing group substitutions. This platform can deposit multiple film types (silicon nitride, silicon oxide, silicon oxynitride) by varying the reactant gas, thereby increasing precursor versatility and availability.
Solution Approach 2:
The patent designs composite precursor molecules that integrate multiple functional elements (silicon center, chalcogen ligands, electron-withdrawing groups) into a single molecular structure. This composite approach enables simultaneous achievement of thermal stability, high reactivity, and volatility in a single precursor molecule.
4Manufacturing precision
If CVD is used for deposition, then layer deposition occurs, but precise control of substrate temperature and precursors is required which increases chamber design complexity
Solution Approach 1:
The patent changes the volatility and reactivity parameters of the precursor to enable deposition at lower temperatures with reduced sensitivity to temperature gradients. This reduces the complexity of temperature control systems and chamber design while maintaining layer uniformity.
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 enables the formation of high-quality silicon nitride, silicon oxide, and silicon oxynitride films with minimal halogen contamination, suitable for various substrates, including temperature-sensitive ones, while maintaining process control and uniformity.
Implementation Method 1
Cyclical deposition is based upon atomic layer epitaxy (ALE) and employs chemisorption techniques to deliver precursor molecules on a substrate surface in sequential cycles
Implementation Method 2
Chemical vapor deposition (CVD) is one of the most common deposition processes employed for depositing layers on a substrate
Data Source
AI summary
Chalcogen silane precursors having electron withdrawing groups are described. Methods for depositing one or more of a silicon nitride (SixNy) film, a silicon oxide (SiOx) film, or a silicon oxynitride (SiOxNz) on a substrate are described. The substrate is exposed to the chalcogen silane precursor and a reactant to deposit the silicon nitride (SixNy) film, the silicon oxide (SiOx) film, and/or the silicon oxynitride (SiOxNz) film. The exposures can be sequential or simultaneous. The chalcogen silane may be substantially free of halogen. The chalcogen may be selected from the group consisting of sulfur (S), selenium (Se), and tellurium (Te).