Monocrystalline Silicon Growth via Magnetic Field Nitrogen Doping
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Solution Overview
Problem
The Czochralski method for growing monocrystalline silicon introduces oxygen impurities from quartz crucibles, leading to defects in integrated circuits, and existing nitrogen doping methods face challenges in controlling purity and homogeneity, particularly with the reduced thermal budget in ultra-large-scale integrated circuit manufacturing.
Innovation Solution
A method combining solid-phase nitrogen doping with a magnetic field in the Czochralski process, where a gas containing argon is introduced during melt formation, and a magnetic field is applied during crystal pulling, allowing precise control of nitrogen concentration and distribution, enhancing oxygen precipitation and mechanical strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If solid-phase nitrogen doping is applied to control nitrogen concentration, then nitrogen concentration can be controlled, but Si3N4 particles remain and dislocation defects are formed
Solution Approach 1:
The patent introduces an intermediary substance (silicon nitride layer) that facilitates nitrogen doping without directly introducing solid particles. The silicon nitride layer is deposited on the crucible wall and serves as a nitrogen source, allowing controlled nitrogen diffusion into the silicon melt while avoiding the formation of unwanted Si3N4 particles and dislocation defects that occur with direct solid-phase doping
2Reliability
If gas-phase nitrogen doping is applied to achieve high purity, then purity is relatively high, but nitrogen concentration is difficult to control due to thermal convection dependence
Solution Approach 1:
The patent replaces the purely thermal convection-based gas-phase doping mechanism with a magnetic field-assisted approach. By applying a magnetic field during the doping process, the patent controls the fluid flow and heat transfer patterns in the silicon melt, enabling precise control of nitrogen concentration while maintaining high purity. This magnetic field control mechanism supplements or replaces the insufficient thermal convection control
3Reliability
If oxygen concentration is reduced to prevent defects in source area, then defect formation is prevented, but intrinsic gettering effect is adversely affected due to reduced thermal budget
Solution Approach 1:
The patent changes the doping parameter by introducing nitrogen at controlled concentrations (1×10^13 to 1×10^16 atoms/cm³) during the crystal growth process. This parameter change enables the formation of oxygen precipitation defects at lower oxygen concentrations, maintaining the intrinsic gettering effect while preventing defects in the source area. The magnetic field assistance ensures uniform nitrogen distribution for consistent gettering performance
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 achieves high-density, homogeneous oxygen precipitation near the silicon wafer surface, reducing defects and improving the intrinsic gettering effect, while maintaining high purity and mechanical strength, suitable for ultra-large-scale integrated circuits.
Implementation Method 1
applying a magnetic field during the pulling step
Implementation Method 2
introducing a gas containing argon during formation of the melt
Implementation Method 3
Nitrogen is able to facilitate oxygen precipitation within monocrystalline silicon; therefore the intrinsic gettering effect can be enhanced
Data Source
AI summary
This invention provides a method for growing monocrystalline silicon by applying Czochralski method comprising forming a melt of silicon-containing materials in a crucible and pulling the melt for monocrystalline silicon growth, which is characterized by, introducing a gas containing argon during formation of the melt, and, applying a magnetic field during the pulling step. This invention also provides a method for producing a wafer based on the above monocrystalline silicon.