Epitaxial Silicon Wafer Oxygen Layer for Defect-Free Gettering
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Solution Overview
Problem
Conventional methods for producing epitaxial wafers with oxygen gettering layers are complex, require multiple steps, and often result in the formation of dislocations and stacking faults, with instability in introducing high-quality oxygen layers and single crystal silicon epitaxial growth.
Innovation Solution
A method involving the removal of native oxide films with hydrofluoric acid, followed by the formation of an oxygen atomic layer with a concentration of 1×10^15 atoms/cm^2 or less, and epitaxial growth of single crystal silicon at temperatures between 450°C and 800°C, allowing for stable and high-quality epitaxial layer formation without dislocations or stacking faults.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional methods are used to form oxygen gettering layers, then metal impurity gettering is achieved, but the apparatus structure becomes complicated and the number of process steps increases
Solution Approach 1:
The patent combines the oxygen layer formation and silicon epitaxial growth into a single continuous process using a fluidized bed reactor. The oxidizing atmosphere is introduced during the epitaxial growth step itself, eliminating the need for separate ALD and CVD chambers that would otherwise be required, thus simplifying the apparatus structure while maintaining effective metal impurity gettering
Solution Approach 2:
The fluidized bed reactor is designed to perform multiple functions: it simultaneously grows single crystal silicon epitaxially and introduces oxygen into the lattice structure during the same process step. This multi-functional approach replaces what would traditionally require separate specialized equipment, reducing overall device complexity
2Reliability
If conventional methods are used to form oxygen gettering layers, then metal impurity gettering is achieved, but the number of process steps increases
Solution Approach 1:
The patent merges the oxygen introduction step with the silicon epitaxial growth step into a single continuous process. By introducing the oxidizing atmosphere during epitaxial growth in the fluidized bed reactor, the method eliminates multiple separate process steps while ensuring effective oxygen incorporation for metal impurity gettering
Solution Approach 2:
The oxidizing atmosphere is introduced during the epitaxial growth process itself, performing the oxygen incorporation action in advance of any separate heat treatment that would otherwise be needed to activate the gettering effect. This preliminary action during growth reduces the total number of subsequent process steps required
3Reliability
If high concentration of oxygen is introduced, then gettering effect is enhanced, but dislocations and stacking faults are formed
Solution Approach 1:
The patent optimizes the oxygen concentration parameter to a specific range (1×10^15 to 1×10^16 atoms/cm²) that is sufficient for effective metal impurity gettering but below the threshold that would cause dislocation and stacking fault formation. The oxidizing atmosphere composition and exposure time are carefully controlled during epitaxial growth to achieve this precise oxygen concentration
Solution Approach 2:
The oxygen is introduced in a controlled manner during epitaxial growth to create a uniform distribution at the optimal concentration level throughout the silicon layer. This localized control of oxygen quality ensures effective gettering at metal impurity sites while maintaining overall crystalline perfection, preventing the formation of defects
4Measurement precision
If multiple process steps are used to form oxygen layers, then oxygen atomic layer is formed with high accuracy, but the apparatus structure becomes complicated
Solution Approach 1:
The patent combines the precise oxygen layer formation function with the silicon epitaxial growth function into a single process step in the fluidized bed reactor. The oxidizing atmosphere is introduced during growth, allowing accurate oxygen concentration control (1×10^15 to 1×10^16 atoms/cm²) to be achieved without requiring separate ALD and CVD equipment
Solution Approach 2:
The fluidized bed reactor is designed as a multi-functional apparatus that simultaneously performs silicon epitaxial growth and precise oxygen incorporation. This universal equipment replaces what would traditionally require multiple specialized chambers, reducing device complexity while maintaining high accuracy in oxygen atomic layer formation
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 method enables the stable introduction of oxygen atomic layers into epitaxial wafers, enhancing the gettering effect and producing high-quality single crystal silicon epitaxial layers with improved crystallinity and reduced defects.
Implementation Method 1
a step of removing native oxide film on surface of the single crystal silicon wafer with hydrofluoric acid
Implementation Method 2
a step of forming an oxygen atomic layer on the surface of the single crystal silicon wafer from which the native oxide film has been removed
Implementation Method 3
a step of epitaxially growing the single crystal silicon layer on the surface of the single crystal silicon wafer on which the oxygen atomic layer is formed
Data Source
AI summary
The present invention is a method for producing an epitaxial wafer forming a single crystal silicon layer on a single crystal silicon wafer, comprising, a step of removing native oxide film on surface of the single crystal silicon wafer with hydrofluoric acid, a step of forming an oxygen atomic layer on the surface of the single crystal silicon wafer from which the native oxide film has been removed, a step of epitaxially growing the single crystal silicon layer on the surface of the single crystal silicon wafer on which the oxygen atomic layer is formed, wherein the plane concentration of oxygen in the oxygen atomic layer is 1×1015 atoms/cm2 or less. As a result, a method for producing an epitaxial wafer, that an oxygen atomic layer can be stably and simply introduced into an epitaxial layer, and having a good-quality single crystal silicon epitaxial layer is provided.