Low-HF RTWCG Formulation for SiOX Dielectric Growth
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Solution Overview
Problem
Current Room Temperature Wet Chemical Growth (RTWCG) methods for SiOX thin film dielectrics face challenges with low deposition rates, poor adhesion to silicon surfaces, and high metallic and non-metallic impurity concentrations, which affect the electric and dielectric properties of the films, and require high HF concentrations, limiting their practicality and efficiency.
Innovation Solution
A low-[HF] RTWCG formulation is developed, incorporating iodine-containing compounds, fluoride-containing acids, non-oxidizing acids, and pyridine compounds, which reduces the consumption rate of the growth solution, improves adhesion, and enhances the growth rate and dielectric properties of SiOX thin films, while maintaining a stable oxidation state and bath life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional RTWCG methods use high HF concentrations to achieve acceptable growth rates, then the deposition rate improves, but the impurity concentration increases and dielectric properties deteriorate
Solution Approach 1:
The invention changes the chemical parameters of the growth solution by replacing HF with non-oxidizing acids (HCl, H2SO4, H3PO4) and adding iodine compounds and pyridine compounds. This parameter change allows achieving acceptable deposition rates (up to 360 Å/hour) without the harmful effects of high HF concentration, thereby maintaining good dielectric properties with impurity concentrations below 1 part per million
Solution Approach 2:
The invention introduces intermediary substances (iodine compounds and pyridine compounds) that mediate the chemical reaction between the silicon substrate and the growth solution. These intermediaries enable the growth process to proceed at acceptable rates without requiring high HF concentrations, thus resolving the contradiction between deposition rate and dielectric quality
2Temperature
If LPD method is used to deposit SiO2 at room temperature, then the process temperature is reduced, but the deposition rate becomes very low (less than 25 nm/hour)
Solution Approach 1:
The invention changes the chemical composition parameters of the growth solution by incorporating iodine compounds and pyridine compounds along with non-oxidizing acids. This chemical parameter change enables the reaction to proceed at room temperature while achieving much higher deposition rates (up to 360 Å/hour) compared to conventional LPD methods
Solution Approach 2:
The invention uses a composite chemical formulation combining multiple components (non-oxidizing acids, iodine compounds, pyridine compounds) that work synergistically to achieve both low temperature operation and high deposition rates, overcoming the limitations of single-component LPD systems
3Productivity
If high HF concentration formulations are used in RTWCG, then the growth rate improves, but the bath life is reduced due to rapid consumption
Solution Approach 1:
The invention changes the acid concentration parameters by replacing HF with non-oxidizing acids at optimized concentrations (1-50%). This parameter change results in slower chemical consumption rates, extending bath life from hours to days or weeks, while maintaining acceptable growth rates through the catalytic action of iodine and pyridine compounds
4Device complexity
If conventional RTWCG formulations are used, then the process is simple, but the impurity concentration in the deposited film is high
Solution Approach 1:
The invention introduces iodine compounds and pyridine compounds as intermediary substances that mediate the deposition process. These intermediaries enable precise control over the growth reaction, resulting in ultra-low impurity concentrations (below 1 part per million) in the deposited films, despite the increased formulation complexity
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 low-[HF] RTWCG formulation achieves improved growth rates, reduced impurity concentrations, and enhanced dielectric properties, along with extended bath life, making it more suitable for electronic and photonic device applications, and reduces reflective losses in solar cells.
Implementation Method 1
The liquid composition reacts with a silicon substrate to deposit a silicon oxide layer thereon
Implementation Method 2
Room Temperature Wet Chemical Growth (RTWCG) method and process
Data Source
AI summary
This present invention relates to a Room Temperature Wet Chemical Growth (RTWCG) formulations, methods and processes. In one embodiment, the present invention further relates to RTWCG formulations, methods and processes that utilize a low-[HF]. In another embodiment, the present invention relates to RTWCG formulations with improved bath life.