Single Crystal Growth via Liquid-Phase Temperature Gradient Control
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Solution Overview
Problem
Conventional methods for growing high-quality single crystals face challenges such as long processing times, low productivity, and inability to effectively control temperature gradients, leading to defects and reduced yield rates.
Innovation Solution
A method involving a controlled temperature gradient in the melt, where the temperature increases gradually to a maximum point and then decreases along the axis of the single crystal, with a greater increasing gradient than decreasing gradient, optimized using techniques like Czochralski or Bridgman methods, to enhance crystal growth and reduce defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional solid-phase temperature control methods are used, then thermal stress is reduced, but processing time becomes too long (16 hours or more)
Solution Approach 1:
The invention changes the temperature control parameters from solid-phase to liquid-phase, applying temperature gradients to the melt rather than the solid crystal. This fundamental parameter change enables much faster processing (reducing time from 16+ hours to practical production times) while still achieving thermal stress control through the liquid phase temperature distribution.
Solution Approach 2:
The invention utilizes the liquid phase of the material during crystal growth, controlling temperature gradients in the melt rather than in the solid crystal. By performing temperature control in the liquid phase where heat transfer is more efficient, the process achieves both thermal stress management and dramatically reduced processing time.
2Reliability
If conventional solid-phase temperature control is applied, then some defect reduction is achieved, but large-scale production cannot be provided
Solution Approach 1:
The invention transitions from solid-phase to liquid-phase temperature control, enabling faster heat transfer and more efficient processing. This parameter change allows the process to be scaled up for large-scale production while maintaining defect reduction capabilities, as the liquid phase responds more quickly to temperature changes.
Solution Approach 2:
The invention replaces the slow thermal diffusion mechanism in solids with the more efficient convective and conductive heat transfer in liquids. This substitution of the thermal transport mechanism enables both defect reduction and high-speed production suitable for large-scale manufacturing.
3Manufacturing precision
If conventional pulling rates are used, then some crystal quality is maintained, but productivity is too low (0.4 mm/min)
Solution Approach 1:
The invention changes the temperature control from solid-phase to liquid-phase, enabling much higher pulling rates. The liquid phase temperature gradients can be adjusted rapidly and uniformly, allowing the crystal to be pulled at higher speeds without compromising quality, thus dramatically increasing productivity.
Solution Approach 2:
The invention introduces dynamic temperature control in the liquid phase, where temperature gradients can be rapidly adjusted and optimized during the crystal growth process. This dynamic control allows for higher pulling rates while maintaining crystal quality, as the liquid phase can adapt quickly to changing growth conditions.
4Manufacturing precision
If solid-liquid interface control is applied, then some crystal quality improvement is achieved, but high quality single crystals cannot be obtained
Solution Approach 1:
The invention changes the control target from the solid-liquid interface to the liquid phase temperature distribution. By controlling temperature gradients in the melt, the invention achieves better overall crystal quality than interface control alone, as the liquid phase control affects the entire growth zone and enables superior defect reduction.
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 significantly increases the growth rate and quality of single crystals by restraining point defects and improving productivity, achieving a 20-40% increase in growth rate compared to conventional methods.
Implementation Method 1
the convection of the inner region of the melt is made smaller than that of the outer region thereof
Implementation Method 2
making the temperature of a melt increase gradually to a maximum point and then decrease gradually along the axis parallel to the lengthwise direction of the single crystal from the crystal-melt interface to the bottom of the crucible
Data Source
AI summary
Disclosed is a method of growing a single crystal from a melt contained in a crucible. The method includes the step of making the temperature of a melt increase gradually to a maximum point and then decrease gradually along the axis parallel to the lengthwise direction of the single crystal from the interface of the single crystal and the melt to the bottom of the crucible. The increasing temperature of the melt is kept to preferably have a greater temperature gradient than the decreasing temperature thereof. Preferably, the axis is set to pass through the center of the single crystal. Preferably, the convection of the inner region of the melt is made smaller than that of the outer region thereof.