CZ Crucible Gap Structure for Stable Quartz Support
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The quartz glass crucible becomes unstable and prone to damage due to point contact with the graphite crucible during single crystal silicon production, leading to uneven heat supply and quality degradation of the silicon ingot.
Innovation Solution
A CZ crucible design with a gap between the inner surface of the graphite crucible and the outer surface of the quartz glass crucible on the central axis, ensuring contactless contact and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the quartz glass crucible outer surface is shaped to have a convex curved surface to follow the shape of the inner surface of the graphite crucible, then the contact area between the crucibles is increased, but manufacturing errors still result in point contact at the bottom portion, causing instability
Solution Approach 1:
Instead of making the outer surface of the quartz glass crucible convex to follow the inner surface of the graphite crucible, the invention inverts the approach by making the outer surface flat and the inner surface of the graphite crucible convex. This inversion eliminates point contact at the bottom portion while maintaining stable support, as the flat outer surface of the quartz glass crucible can uniformly contact the convex inner surface of the graphite crucible without concentration of contact stress.
2Reliability
If trial-and-error selection of compatible quartz glass crucible and graphite crucible is performed, then a stable combination may be achieved, but the manufacturing efficiency is significantly reduced
Solution Approach 1:
The invention changes the geometric parameters of the crucible interfaces: the outer surface of the quartz glass crucible is made flat (changing from convex to flat), and the inner surface of the graphite crucible is made convex with a specific radius of curvature. This parameter change ensures stable combination without requiring trial-and-error selection, as the geometric design inherently provides uniform contact and stability.
3Device complexity
If point contact occurs at the bottom portion of the quartz glass crucible, then the structure is simpler, but the quartz glass crucible becomes unstable and prone to damage during operation
Solution Approach 1:
The invention applies preliminary action by pre-designing the interface geometry between the quartz glass crucible and graphite crucible to prevent point contact before operation begins. The flat outer surface of the quartz glass crucible and convex inner surface of the graphite crucible are designed in advance to ensure uniform contact distribution, preventing concentration of stress that would lead to damage during operation.
Data Source
AI summary
A CZ crucible for growing a single crystal silicon ingot by a CZ method, where the CZ crucible includes a closed-end cylindrical graphite crucible and a closed-end cylindrical quartz glass crucible disposed inside the graphite crucible, and the CZ crucible includes a gap between an inner surface of a bottom portion of the graphite crucible and an outer surface of a bottom portion of the quartz glass crucible on a central axis of the CZ crucible, the gap keeping the inner surface of the bottom portion of the graphite crucible and the outer surface of the bottom portion of the quartz glass crucible contactless with each other. This provides a CZ crucible that ensures that a closed-end cylindrical quartz glass crucible for growing a single crystal silicon ingot by a CZ method can be stable and self-supporting when disposed inside a closed-end cylindrical graphite crucible.