Silicon Substrate Carbon Diffusion Layer Dislocation Inhibition
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Solution Overview
Problem
Existing methods for inhibiting slip dislocation in silicon single-crystal substrates using carbon diffusion layers are insufficient due to low carbon concentration and thin layer thickness, which fail to provide adequate proximity gettering and surface strength.
Innovation Solution
A method involving RTA treatment in a carbon-containing gas atmosphere to form a 3C-SiC single-crystal film, followed by oxidation to create a thick carbon diffusion layer with a concentration of 1×10^17 atoms/cm^3 or more and a thickness of 2 μm or more, enhancing surface strength and dislocation inhibition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a carbon diffusion layer is formed by heat treatment in a carbon-containing gas atmosphere, then carbon concentration in the surface layer can be increased, but the layer thickness is limited to 200 nm or less which is insufficient for effectively inhibiting slip dislocation
Solution Approach 1:
The invention divides the carbon diffusion process into two distinct stages: first forming a thin 3C-SiC single-crystal film (7-200 nm) on the silicon substrate surface, then oxidizing this film to create a thicker carbon diffusion layer (2-10 μm). This segmentation allows achieving both high carbon concentration and sufficient layer thickness, resolving the contradiction between quantity of carbon and depth of penetration.
Solution Approach 2:
The invention utilizes phase transitions of carbon: first forming crystalline 3C-SiC single-crystal film from gaseous carbon sources, then transforming this crystalline carbon layer into an oxidized state (SiO2 with embedded carbon) through thermal oxidation. This phase transition mechanism enables the carbon to be introduced at high concentration while forming a sufficiently thick layer that effectively inhibits slip dislocation.
2Reliability
If nitrogen is injected into the surface layer by heat treatment, then proximity gettering ability can be imparted, but the large diffusion coefficient of nitrogen causes high outward diffusion rate and fails to sufficiently increase nitrogen concentration in the surface layer
Solution Approach 1:
The invention changes the diffusing element from nitrogen to carbon, fundamentally altering the diffusion parameter. Carbon has a much smaller diffusion coefficient in silicon compared to nitrogen, allowing carbon to be retained in the surface layer at high concentrations without excessive outward diffusion. This parameter change enables simultaneous achievement of high concentration and effective proximity gettering.
3Quantity of substance
If a thin carbon diffusion layer (200 nm or less) is formed, then carbon concentration can be increased to 1×10^18 to 1×10^20 atoms/cm³, but such a thin layer is insufficient for more certainly inhibiting slip dislocation
Solution Approach 1:
The invention transitions from a thin surface-layer approach (200 nm or less) to a deeper carbon diffusion layer (2-10 μm thick). By extending the carbon-enriched region into the bulk substrate, the invention creates a three-dimensional carbon distribution that provides more effective mechanical reinforcement and dislocation inhibition while maintaining high carbon concentration through the oxidation process.
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 forms a silicon single-crystal substrate with high surface strength and reduced dislocation generation, achieving improved proximity gettering and surface stability.
Implementation Method 1
adhering carbon on a surface of a silicon single-crystal substrate by an RTA treatment of the silicon single-crystal substrate in a carbon-containing gas atmosphere
Implementation Method 2
forming a 3C-SiC single-crystal film on the surface of the silicon single-crystal substrate by reacting the carbon and the silicon single-crystal substrate
Implementation Method 3
oxidizing the 3C-SiC single-crystal film to be an oxide film and diffusing carbon inward the silicon single-crystal substrate
Implementation Method 4
diffusing carbon inward the silicon single-crystal substrate by an RTA treatment of the silicon single-crystal substrate on which the 3C-SiC single-crystal film is formed
Data Source
AI summary
A method for manufacturing a silicon single-crystal substrate having a carbon diffusion layer on a surface, proximity gettering ability, and high strength near the surface, and hardly generating dislocation or extending dislocation, includes: a step of adhering carbon on a surface of a silicon single-crystal substrate by an RTA treatment of the silicon single-crystal substrate in a carbon-containing gas atmosphere; a step of forming a 3C-SiC single-crystal film on the surface of the silicon single-crystal substrate by reacting the carbon and the silicon single-crystal substrate; a step of oxidizing the 3C-SiC single-crystal film to be an oxide film and diffusing carbon inward the silicon single-crystal substrate by an RTA treatment of the silicon single-crystal substrate on which the 3C-SiC single-crystal film is formed, the RTA treatment being performed in an oxidative atmosphere; and a step of removing the oxide film.