Horizontal Magnetic Field Czochralski Ingot Growth Time Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional horizontal magnetic field Czochralski methods for producing monocrystalline silicon ingots require longer process times, necessitating a need for methods to reduce the formation time while maintaining high quality.
Innovation Solution
The method involves pulling a neck from the silicon melt without applying a horizontal magnetic field and then applying it during the growth of the ingot main body, with the magnetic field being either absent or present at a low flux density of 1500 gauss or less during neck growth, and increasing the crucible rotation rate and reflector distance to enhance melt convection and reduce dislocations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a horizontal magnetic field is applied during the entire Czochralski process, then the nanotopology and dopant distribution are improved, but the process time is significantly extended
Solution Approach 1:
The Czochralski process is divided into distinct stages: neck formation without magnetic field, crown formation with magnetic field, and body formation with magnetic field. This segmentation allows the magnetic field to be applied only during stages where it provides benefit, rather than throughout the entire process.
Solution Approach 2:
The neck is formed in advance without magnetic field to establish a foundation for subsequent crystal growth. This preliminary action without magnetic field prevents the time penalty while still enabling the later application of magnetic field during critical growth phases.
2Stability of the object's composition
If a horizontal magnetic field is applied during neck growth, then the melt temperature stability is improved, but the process time is extended
Solution Approach 1:
The process separates neck formation from the magnetic field application, assigning different functions to different stages. The neck stage focuses on establishing crystal structure without magnetic field interference, while subsequent stages benefit from magnetic field stabilization.
Solution Approach 2:
Instead of applying magnetic field during the entire process including neck formation, the patent applies it partially during only the crown and body formation stages where it provides the most benefit for temperature stability and quality.
3Manufacturing precision
If the crown height is increased to ensure zero dislocation growth, then the crystal quality is improved, but the process time is extended
Solution Approach 1:
The magnetic field is dynamically applied during crown and body formation to actively suppress dislocation generation, enabling faster growth rates while maintaining zero dislocation quality. This dynamic control allows optimization of both speed and quality.
Solution Approach 2:
The magnetic field strength and other process parameters are optimized during crown and body formation to enable faster growth rates while maintaining zero dislocation quality, reducing the time penalty associated with traditional methods.
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 reduces the overall process time for ingot formation, minimizes dislocations, and allows for the production of high-quality monocrystalline silicon ingots by optimizing growth conditions such as crucible rotation and magnetic field application.
Implementation Method 1
Strong convection control under horizontal magnetic field Czochralski enables a relatively smooth axial diameter profile
Implementation Method 2
A seed crystal is contacted with a silicon melt held within a crucible. A neck is pulled from the silicon melt.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Methods for producing monocrystalline silicon ingots by horizontal magnetic field Czochralski are disclosed. During growth of the neck and/or growth of at least a portion of the crown, a magnetic field is not applied to the neck and/or crown or a relatively weak magnetic field of 1500 gauss or less is applied. A horizontal magnetic field (e. g., greater than 1500 gauss) is applied during growth of the ingot main body.