SiGe Epitaxy Surface Preparation for Native Oxide and Residue Removal
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Solution Overview
Problem
Existing methods for manufacturing semiconductor devices with silicon-germanium films face challenges in effectively removing native oxide films and impurities, which can lead to defects in the epitaxially grown films.
Innovation Solution
A substrate processing method involving a series of steps: cleaning the substrate with liquid bath cleaning processes, performing a chemical oxide removal process using fluorine and basic gases to remove the native oxide film, followed by a hydrogen bake reduction process to further clean the substrate. This is followed by a pre-clean process using a mixed gas of germanium-containing gas diluted with hydrogen, which removes residual COR process residues and impurities. Finally, silicon and silicon-germanium films are formed by epitaxial growth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional cleaning methods are used to remove native oxide films, then the oxide removal efficiency is insufficient, but increasing the aggressiveness of cleaning causes defects in the epitaxially grown films
Solution Approach 1:
The cleaning process is divided into multiple sequential stages: chemical oxide removal (COR) using fluorine-containing gas and basic gas to remove the native oxide film, followed by hydrogen bake reduction to remove corrosion residues, and finally pre-cleaning with germanium-containing gas diluted with hydrogen. This segmentation allows each step to address specific cleaning needs without causing film defects
Solution Approach 2:
The patent performs preliminary cleaning actions before epitaxial growth by removing the native oxide film and performing multiple cleaning steps. The hydrogen bake reduction is performed before the pre-cleaning step to remove corrosion residues, preparing the substrate surface in advance for high-quality epitaxial growth without introducing defects
2Manufacturing precision
If multiple cleaning steps are performed to remove impurities, then the substrate cleanliness is improved, but the processing time increases
Solution Approach 1:
The patent combines multiple cleaning functions into a unified gas-phase processing sequence. The hydrogen bake reduction and pre-cleaning with germanium-containing gas are performed in the same epitaxial growth chamber without breaking vacuum, merging the cleaning function with the preparation for film growth. This integration achieves thorough cleaning while minimizing the time loss associated with chamber evacuation and repressurization
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 method effectively reduces defects in the silicon-germanium film by thoroughly cleaning the substrate surface, ensuring high-quality film formation with reduced impurity incorporation.
Implementation Method 1
supplying a fluorine containing gas and a basic gas to the substrate having the silicon oxide film to remove the silicon oxide film
Implementation Method 2
supplying a hydrogen gas to the substrate in which the silicon oxide film is removed and applying a thermal treatment to the substrate
Implementation Method 3
supplying a mixed gas of a germanium containing gas diluted with a hydrogen gas to the substrate to which the thermal treatment is applied to perform pre-cleaning of the substrate
Implementation Method 4
forming a silicon germanium film by epitaxial growth on the substrate to which the pre-cleaning is performed
Data Source
AI summary
A substrate processing method includes: preparing a substrate in which a silicon oxide film is formed on a surface of a silicon substrate; supplying a fluorine containing gas and a basic gas to the substrate having the silicon oxide film to remove the silicon oxide film; supplying a hydrogen gas to the substrate in which the silicon oxide film is removed and applying a thermal treatment to the substrate; supplying a mixed gas of a germanium containing gas diluted with a hydrogen gas to the substrate to which the thermal treatment is applied to perform pre-cleaning of the substrate; and forming a silicon germanium film by epitaxial growth on the substrate to which the pre-cleaning is performed.