Side Heater Length Optimization for Silicon Ingot Thermal Efficiency
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Solution Overview
Problem
Conventional ingot puller apparatuses face inefficiencies in reducing oxygen input from the crucible during ingot growth, with long side heaters decreasing thermal efficiency and increasing energy consumption, and methods involving magnetic fields are costly.
Innovation Solution
Selecting the length of the side heater in an ingot puller apparatus through thermal simulations to optimize the crucible temperature profile, reducing oxygen input by varying the side heater length to minimize crucible floor temperature and maintain thermal efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If insulation is removed toward the bottom of the hot zone to reduce oxygen input into the melt, then oxygen dissolution from the crucible is reduced, but side heater energy input increases thereby decreasing thermal efficiency
Solution Approach 1:
The invention changes the geometric parameter of the side heater (length) to optimize the temperature profile in the melt. By selecting a specific side heater length, the system achieves the dual goal of maintaining low crucible floor temperatures (reducing oxygen dissolution) while preserving thermal efficiency, thus resolving the contradiction between reducing oxygen input and maintaining energy efficiency
2Temperature
If a relatively long side heater is used in the ingot puller hot zone, then temperature control is improved, but the heater heats the bottom of the crucible and shaft further decreasing energy efficiency
Solution Approach 1:
The invention optimizes the side heater length parameter to achieve effective temperature control in the melt without excessive heating of the crucible bottom and shaft. The selected side heater length provides sufficient radial heating while minimizing unwanted heating of surrounding components, thus maintaining energy efficiency
3Object-affected harmful factors
If magnetic field is applied to dampen melt flows and reduce oxygen transport, then oxygen input from crucible is reduced, but capital cost and operating cost increase significantly
Solution Approach 1:
The invention extracts the oxygen reduction function from the complex and expensive magnetic field system and achieves it through a simpler geometric modification of the side heater length. This eliminates the need for additional magnetic field generation equipment while still achieving reduced oxygen dissolution and transport
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 oxygen uptake in ingots, enhances thermal efficiency, and allows for consistent resistivity in silicon production, achieving lower oxygen concentrations and reduced energy consumption.
Implementation Method 1
A side heater disposed radially outward to the crucible sidewall is provided. The side heater has the selected side heater length.
Implementation Method 2
A bottom heater disposed below the crucible floor.
Implementation Method 3
Selecting the length of the side heater includes modeling a temperature profile of the crucible in the ingot puller apparatus while withdrawing an ingot from the silicon melt in two or more thermal simulations.
Data Source
AI summary
Methods for preparing an ingot in an ingot puller apparatus are disclosed. Thermal simulations are performed with the length of the ingot puller apparatus side heater being varied in the thermal simulations. A side heater is selected based on the thermal simulations. An ingot puller apparatus having the selected side heater length is provided. A seed crystal is lowered into a melt within a crucible of the ingot puller apparatus and an ingot is withdrawn from the melt.