Group 7 Element Doping for Rare-Earth Oxyorthosilicate Crystal Growth Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Growth instabilities in large crystals grown using the Czochralski method, such as spiral shape deviations and thermal stress, often result in crystal shattering due to impurities and variations in thermal expansion coefficients, which are not effectively addressed by existing methods.
Innovation Solution
Incorporating a group 7 element, such as manganese or rhenium, into the melt during the growth of rare-earth oxyorthosilicate crystals using the Czochralski method, which suppresses growth instabilities and enhances scintillation performance by maintaining uniform light emission and energy resolution across the crystal boule.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the Czochralski method is used to grow large crystals, then crystal size increases, but growth instabilities occur leading to spiral shape deviations and thermal stress
Solution Approach 1:
The invention changes the chemical composition parameter of the melt by adding group 7 elements (Mn, Re) to suppress growth instabilities. This compositional modification alters the melt's properties to prevent spiral growth and thermal stress, enabling stable growth of large crystals while maintaining cylindrical shape uniformity.
Solution Approach 2:
Group 7 elements act as intermediary substances added to the melt to mediate between the seed crystal and the bulk melt. These elements suppress the accumulation of impurities and excess melt constituents at the crystal-melt interface, thereby stabilizing the growth process and preventing spiral deviations without affecting the final crystal composition significantly.
2Volume of moving object
If the Czochralski method is used to grow large crystals, then crystal size increases, but thermal stress causes crystal shattering
Solution Approach 1:
The invention modifies the melt composition by incorporating group 7 elements to control thermal expansion behavior during crystal growth. This parameter change reduces variations in thermal expansion coefficients within the crystal, thereby minimizing thermal stress accumulation and preventing crystal shattering in large-sized crystals.
Solution Approach 2:
The group 7 elements provide beforehand cushioning by pre-suppressing growth instabilities and uniforming thermal properties during the growth process. This preventive measure reduces thermal stress buildup before it can reach critical levels that would cause crystal shattering, ensuring structural integrity throughout the crystal.
3Device complexity
If conventional melts are used, then growth process is simple, but impurities accumulate at the crystal-melt interface causing growth instabilities
Solution Approach 1:
Group 7 elements serve as intermediary substances in the melt that actively suppress impurity accumulation at the crystal-melt interface. These elements modify the melt's chemical environment to prevent the formation of unstable molecular complexes, thereby ensuring reliable and stable crystal growth without significantly complicating the overall process.
Solution Approach 2:
The invention changes the chemical composition parameter of the melt by adding group 7 elements, which fundamentally alters the melt's behavior regarding impurity accumulation. This parameter modification enhances growth reliability by preventing the formation of excess molecular complexes and maintaining a stable crystal-melt interface throughout the growth process.
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
The addition of a group 7 element to the melt significantly reduces growth instabilities and improves scintillation efficiency and uniformity, resulting in crystals with superior scintillation properties and reduced thermal stress, as evidenced by consistent light output and energy resolution from top to bottom of the boule.
Implementation Method 1
Growth instabilities may result in stresses due to variations in thermal expansion coefficients within the crystal
Implementation Method 2
A crystal grows on the seed as it is withdrawn
Implementation Method 3
excesses of melt constituents accumulating at the interface between the surface of the melt and the growing crystal
Data Source
AI summary
Disclosed are a method of growing a rare-earth oxyorthosilicate crystal and a crystal grown using the method. A melt is prepared by melting a first substance including at least one rare-earth element and a second substance including at least one element from group 7 of the periodic table. A seed crystal is brought into contact with the surface of the melt and withdrawn to grow the crystal.