Pub Date : 2025-04-17DOI: 10.1016/j.jcrysgro.2025.128195
Daqing Peng , Chuanhao Li , Qiankun Yang , Kechao Wang , Liangbing Ge , Dongguo Zhang , Weike Luo , Zhonghui Li
In this study, large scale and high-quality AlGaN/GaN heterojunction films epitaxial grown on two-dimensional h-BN grown through metal–organic chemical vapor deposition were prepared on 6-inch 4H-SiC substrates. The crystal quality of GaN films were improved by adopting H2/NH3 etching at high temperature on h-BN surface before AlN nucleation layer deposition. Furthermore, GaN film grown on h-BN/4H-SiC template under 1200 ℃ pretreatment exhibited lower internal stress, which is one third of that grown on SiC substrate directly. Both h-BN grown on 6-inch 4H-SiC substrate and the subsequent epitaxial AlGaN/GaN heterojunction films have excellent uniformity.
{"title":"Large scale epitaxy of AlGaN/GaN heterojunction films on h-BN/4H-SiC templates","authors":"Daqing Peng , Chuanhao Li , Qiankun Yang , Kechao Wang , Liangbing Ge , Dongguo Zhang , Weike Luo , Zhonghui Li","doi":"10.1016/j.jcrysgro.2025.128195","DOIUrl":"10.1016/j.jcrysgro.2025.128195","url":null,"abstract":"<div><div>In this study, large scale and high-quality AlGaN/GaN heterojunction films epitaxial grown on two-dimensional h-BN grown through metal–organic chemical vapor deposition were prepared on 6-inch 4H-SiC substrates. The crystal quality of GaN films were improved by adopting H<sub>2</sub>/NH<sub>3</sub> etching at high temperature on h-BN surface before AlN nucleation layer deposition. Furthermore, GaN film grown on h-BN/4H-SiC template under 1200 ℃ pretreatment exhibited lower internal stress, which is one third of that grown on SiC substrate directly. Both h-BN grown on 6-inch 4H-SiC substrate and the subsequent epitaxial AlGaN/GaN heterojunction films have excellent uniformity.</div></div>","PeriodicalId":353,"journal":{"name":"Journal of Crystal Growth","volume":"663 ","pages":"Article 128195"},"PeriodicalIF":1.7,"publicationDate":"2025-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143845309","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-04-15DOI: 10.1016/j.jcrysgro.2025.128198
Jithin Kuriakose, P. Karuppasamy, P. Ramasamy
The development and examination of nonlinear optical (NLO) single crystals have garnered considerable attention owing to their prospective uses in optoelectronics and photonics. This study successfully grew 4-Chloro-3-nitrobenzophenone (4C3N) single crystals using an indigenously developed Vertical Bridgman method for nonlinear optical applications. This technique guarantees superior crystal quality, consistency, and a substantial defect-free volume, which is critical for optical applications. Notably, we have grown high-quality, bulk-sized crystals with significantly higher transmittance compared to previously reported data. The structural, optical, and thermal characteristics of the 4C3N crystals were analysed using X-ray diffraction (XRD), UV–Vis spectroscopy, and thermogravimetric analysis. UV–visible-NIR spectroscopy revealed a transmittance exceeding 83 % in the visible region, with a cut-off wavelength at 418 nm corresponding to an optical band gap energy of about 2.9 eV. Photoluminescence analysis was performed to evaluate the emission properties of the grown crystal, showing a prominent peak at 585 nm. The thermal stability of the 4C3N crystal was examined using TGA-DTA analysis, which determined its melting temperature to be 113 °C. Photocurrent measurements indicated strong photoconductive properties. Additionally, the Z-scan technique was used to measure third-order nonlinear optical properties, giving a value of 1.389 × 10–9 esu. Thus, the grown 4C3N crystal shows significant potential for nonlinear optical applications.
{"title":"Design and development of transparent vertical Bridgman system and growth of high quality 4-Chloro-3-Nitrobenzophenone single crystal for nonlinear optical applications","authors":"Jithin Kuriakose, P. Karuppasamy, P. Ramasamy","doi":"10.1016/j.jcrysgro.2025.128198","DOIUrl":"10.1016/j.jcrysgro.2025.128198","url":null,"abstract":"<div><div>The development and examination of nonlinear optical (NLO) single crystals have garnered considerable attention owing to their prospective uses in optoelectronics and photonics. This study successfully grew 4-Chloro-3-nitrobenzophenone (4C3N) single crystals using an indigenously developed Vertical Bridgman method for nonlinear optical applications. This technique guarantees superior crystal quality, consistency, and a substantial defect-free volume, which is critical for optical applications. Notably, we have grown high-quality, bulk-sized crystals with significantly higher transmittance compared to previously reported data. The structural, optical, and thermal characteristics of the 4C3N crystals were analysed using X-ray diffraction (XRD), UV–Vis spectroscopy, and thermogravimetric analysis. UV–visible-NIR spectroscopy revealed a transmittance exceeding 83 % in the visible region, with a cut-off wavelength at 418 nm corresponding to an optical band gap energy of about 2.9 eV. Photoluminescence analysis was performed to evaluate the emission properties of the grown crystal, showing a prominent peak at 585 nm. The thermal stability of the 4C3N crystal was examined using TGA-DTA analysis, which determined its melting temperature to be 113 °C. Photocurrent measurements indicated strong photoconductive properties. Additionally, the Z-scan technique was used to measure third-order nonlinear optical properties, giving a value of 1.389 × 10<sup>–9</sup> esu. Thus, the grown 4C3N crystal shows significant potential for nonlinear optical applications.</div></div>","PeriodicalId":353,"journal":{"name":"Journal of Crystal Growth","volume":"663 ","pages":"Article 128198"},"PeriodicalIF":1.7,"publicationDate":"2025-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143847861","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-04-14DOI: 10.1016/j.jcrysgro.2025.128196
Song Zhang , Hui Zhang
CdZnTe crystals with large single-crystal volume have been grown using the travelling heater method. The concentration uniformity, structural defects, and resistivity of the THM crystals were measured. Two planar detectors were fabricated, which achieved a best resolution of 5.12 % at 59.5 keV and a μeτe value of 8.0 × 10−3 cm2/V. A quasi-hemispherical detector was further prepared and achieved a resolution of 2.27 % at 662 keV and a Peak-to-Compton Ratio of 4.76. Progress in crystal growth, processing, detector fabrication and characterization methods and tools contributed to improvement of high-quality CdZnTe crystals for nuclear radiation detectors.
{"title":"Characterization of THM CdZnTe for nuclear radiation detection","authors":"Song Zhang , Hui Zhang","doi":"10.1016/j.jcrysgro.2025.128196","DOIUrl":"10.1016/j.jcrysgro.2025.128196","url":null,"abstract":"<div><div>CdZnTe crystals with large single-crystal volume have been grown using the travelling heater method. The concentration uniformity, structural defects, and resistivity of the THM crystals were measured. Two planar detectors were fabricated, which achieved a best resolution of 5.12 % at 59.5 keV and a μ<sub>e</sub>τ<sub>e</sub> value of 8.0 × 10<sup>−3</sup> cm<sup>2</sup>/V. A quasi-hemispherical detector was further prepared and achieved a resolution of 2.27 % at 662 keV and a Peak-to-Compton Ratio of 4.76. Progress in crystal growth, processing, detector fabrication and characterization methods and tools contributed to improvement of high-quality CdZnTe crystals for nuclear radiation detectors.</div></div>","PeriodicalId":353,"journal":{"name":"Journal of Crystal Growth","volume":"663 ","pages":"Article 128196"},"PeriodicalIF":1.7,"publicationDate":"2025-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143839802","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-04-14DOI: 10.1016/j.jcrysgro.2025.128179
Stefan Jens Merker , Valeria Zittel , Gabriele Benndorf , Marius Grundmann , Harald Krautscheid
In this paper, we report the deposition of copper(I) iodide (CuI) on c-plane sapphire by chemical vapour deposition (CVD). Single crystals of -CuI with an out-of-plane orientation of 111, as determined by X-ray diffraction, were grown on the substrate. The copper precursor used was bis(N,N’-di-sec-butylacetamidinato) dicopper(I). Two different iodine precursors, ethyl iodide (EtI) and 2-iodo-2-methylpropane (tBuI), are discussed in detail. X-ray diffraction and laser scanning microscopy images show the influence of precursor and growth conditions on the morphology and growth rate of CuI. Using tBuI the growth temperature could be lowered and the formation of crystals with flat hexagonal and trigonal shape could be observed. At growth temperatures Tgrowth 230 °C, another CuI phase in addition to -CuI is observed by X-ray diffraction. Photoluminescence measurements show a sharp peak at 380 nm (3.26 eV) that can be assigned to bound excitons of the other CuI phase.
{"title":"Chemical vapour deposition of copper(I) iodide on c-plane sapphire using ethyl iodide and 2-iodo-2-methylpropane","authors":"Stefan Jens Merker , Valeria Zittel , Gabriele Benndorf , Marius Grundmann , Harald Krautscheid","doi":"10.1016/j.jcrysgro.2025.128179","DOIUrl":"10.1016/j.jcrysgro.2025.128179","url":null,"abstract":"<div><div>In this paper, we report the deposition of copper(I) iodide (CuI) on c-plane sapphire by chemical vapour deposition (CVD). Single crystals of <span><math><mi>γ</mi></math></span>-CuI with an out-of-plane orientation of 111, as determined by X-ray diffraction, were grown on the substrate. The copper precursor used was bis(N,N’-di-<em>sec</em>-butylacetamidinato) dicopper(I). Two different iodine precursors, ethyl iodide (EtI) and 2-iodo-2-methylpropane (<sup><em>t</em></sup>BuI), are discussed in detail. X-ray diffraction and laser scanning microscopy images show the influence of precursor and growth conditions on the morphology and growth rate of CuI. Using <sup><em>t</em></sup>BuI the growth temperature could be lowered and the formation of crystals with flat hexagonal and trigonal shape could be observed. At growth temperatures T<sub>growth</sub> <span><math><mo>≤</mo></math></span> 230 °C, another CuI phase in addition to <span><math><mi>γ</mi></math></span>-CuI is observed by X-ray diffraction. Photoluminescence measurements show a sharp peak at 380 nm (3.26 eV) that can be assigned to bound excitons of the other CuI phase.</div></div>","PeriodicalId":353,"journal":{"name":"Journal of Crystal Growth","volume":"663 ","pages":"Article 128179"},"PeriodicalIF":1.7,"publicationDate":"2025-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143847860","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-04-12DOI: 10.1016/j.jcrysgro.2025.128175
Yue Li , Zhijun Wang , Xianghan Gao , Junjie Li , Jincheng Wang , Ke-gang Wang
The precipitation kinetics of particles in solid-state has long been a topic of scientific and industrial interest due to their significant impact on the mechanical properties of Ni-based superalloys. Although numerous studies over the past decades have sought to understand the coarsening mechanism of precipitates, there remains a long-standing debate regarding the dominant mass transport mechanism-whether it is interface-controlled or matrix diffusion-controlled. A key challenge is that analytical theories of coarsening are only valid in the long-time regime, which is difficult to achieve experimentally. To address this, we have developed a modified Kampmann–Wagner numerical (KWN) model that incorporates both mass transport mechanisms. Using this precipitation model, we revisited experimental data from various Ni-Al model alloys at 823K and 1073K to clarify the dominant mass transport mechanisms from nucleation to coarsening. Our study demonstrates that a single mass transport mechanism cannot adequately reproduce the entire set of precipitation data. Specifically, the matrix diffusion mechanism aligns more closely with the early nucleation and growth stages but fails to account for the anomalous effect of increasing volume fraction on the coarsening rate. Conversely, while the interface-controlled mechanism fits the coarsening data better, it does not accurately represent the early nucleation and growth stages. These comparative results highlight the existence of a mixed-mode character throughout the entire precipitation process of particles, which is numerically captured by our modified KWN model.
{"title":"Revealing the mixed-mode precipitation kinetics of γ′ with a modified Kampmann–Wagner numerical (KWN) model","authors":"Yue Li , Zhijun Wang , Xianghan Gao , Junjie Li , Jincheng Wang , Ke-gang Wang","doi":"10.1016/j.jcrysgro.2025.128175","DOIUrl":"10.1016/j.jcrysgro.2025.128175","url":null,"abstract":"<div><div>The precipitation kinetics of <span><math><msup><mrow><mi>γ</mi></mrow><mrow><mo>′</mo></mrow></msup></math></span> particles in solid-state has long been a topic of scientific and industrial interest due to their significant impact on the mechanical properties of Ni-based superalloys. Although numerous studies over the past decades have sought to understand the coarsening mechanism of <span><math><msup><mrow><mi>γ</mi></mrow><mrow><mo>′</mo></mrow></msup></math></span> precipitates, there remains a long-standing debate regarding the dominant mass transport mechanism-whether it is interface-controlled or matrix diffusion-controlled. A key challenge is that analytical theories of coarsening are only valid in the long-time regime, which is difficult to achieve experimentally. To address this, we have developed a modified Kampmann–Wagner numerical (KWN) model that incorporates both mass transport mechanisms. Using this precipitation model, we revisited experimental data from various Ni-Al model alloys at 823K and 1073K to clarify the dominant mass transport mechanisms from nucleation to coarsening. Our study demonstrates that a single mass transport mechanism cannot adequately reproduce the entire set of precipitation data. Specifically, the matrix diffusion mechanism aligns more closely with the early nucleation and growth stages but fails to account for the anomalous effect of increasing volume fraction on the coarsening rate. Conversely, while the interface-controlled mechanism fits the coarsening data better, it does not accurately represent the early nucleation and growth stages. These comparative results highlight the existence of a mixed-mode character throughout the entire precipitation process of <span><math><msup><mrow><mi>γ</mi></mrow><mrow><mo>′</mo></mrow></msup></math></span> particles, which is numerically captured by our modified KWN model.</div></div>","PeriodicalId":353,"journal":{"name":"Journal of Crystal Growth","volume":"663 ","pages":"Article 128175"},"PeriodicalIF":1.7,"publicationDate":"2025-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143851812","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-04-11DOI: 10.1016/j.jcrysgro.2025.128192
Koichi Kakimoto , Taketoshi Tomida , Vladimir V. Kochurikhin , Kei Kamada , Satoshi Nakano , Akira Yoshikawa
The twisting of oxide crystals during their growth process is a major problem that has limited their wider application. We previously conducted three-dimensional analyses that indicated the twisting of beta gallium oxide crystals may be affected by their degree of transparency. In this study, we conducted numerical simulations to study the effects of internal radiation in beta gallium oxide crystals and melts on heat transfer during the Czochralski method. The temperature and velocity distributions in the crystal and melt and the shape of the interface between the crystal and melt were obtained. We used the Rosseland approximation to consider the internal radiation in both the crystal and melt to calculate the heat transfer in the furnace. The results indicated that the temperature gradient was smaller in transparent crystal than in opaque crystal while the temperature gradient was slightly smaller in transparent melt than in opaque melt. These results can be attributed to the radiative heat transfer through the crystal and melt: the crystal faces the cold wall of the furnace, which produces a large heat flux for the heat transfer; meanwhile, the melt faces the hot wall of a crucible, which produces a small heat flux for the heat transfer.
{"title":"Effects of crystal and melt transparency on twisting of β-Ga2O3 crystals grown by the Czochralski method","authors":"Koichi Kakimoto , Taketoshi Tomida , Vladimir V. Kochurikhin , Kei Kamada , Satoshi Nakano , Akira Yoshikawa","doi":"10.1016/j.jcrysgro.2025.128192","DOIUrl":"10.1016/j.jcrysgro.2025.128192","url":null,"abstract":"<div><div>The twisting of oxide crystals during their growth process is a major problem that has limited their wider application. We previously conducted three-dimensional analyses that indicated the twisting of beta gallium oxide crystals may be affected by their degree of transparency. In this study, we conducted numerical simulations to study the effects of internal radiation in beta gallium oxide crystals and melts on heat transfer during the Czochralski method. The temperature and velocity distributions in the crystal and melt and the shape of the interface between the crystal and melt were obtained. We used the Rosseland approximation to consider the internal radiation in both the crystal and melt to calculate the heat transfer in the furnace. The results indicated that the temperature gradient was smaller in transparent crystal than in opaque crystal while the temperature gradient was slightly smaller in transparent melt than in opaque melt. These results can be attributed to the radiative heat transfer through the crystal and melt: the crystal faces the cold wall of the furnace, which produces a large heat flux for the heat transfer; meanwhile, the melt faces the hot wall of a crucible, which produces a small heat flux for the heat transfer.</div></div>","PeriodicalId":353,"journal":{"name":"Journal of Crystal Growth","volume":"663 ","pages":"Article 128192"},"PeriodicalIF":1.7,"publicationDate":"2025-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143845308","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-04-10DOI: 10.1016/j.jcrysgro.2025.128180
Cheng Liu , Nikhil Pokharel , Miguel A. Betancourt Ponce , Qinchen Lin , Padma Gopalan , Chirag Gupta , Shubhra S. Pasayat , Luke Mawst
In this study, we developed ultra-high density InGaN/GaN nanopyramid quantum dots (QD) via Selective Area Growth (SAG) using Metal–Organic Chemical Vapor Deposition (MOCVD). We achieved QDs as small as 23 nm-diameter QDs with a density of 7–10 × 1010 cm−2. The optical and structural properties of these nanostructures were analyzed using Photoluminescence (PL), Scanning Electron Microscope (SEM), X-Ray Diffraction (XRD), and Transmission Electron Microscopy (TEM). Various growth conditions and structure designs including growth temperature, growth rate, TMIn flow rate, and InGaN thickness, were studied to extend the QD emission across the full visible emission range. Power-dependent and temperature-dependent PL measurements were conducted to further investigate the optical properties. An additional longer wavelength QD spectral emission peak was suppressed at low temperatures or higher excitation power, indicating the presence of Shockley-Read-Hall recombination at low injection carrier densities.
{"title":"Full visible range emissions with ultra-high density InGaN/GaN quantum dots achieved by selective area growth","authors":"Cheng Liu , Nikhil Pokharel , Miguel A. Betancourt Ponce , Qinchen Lin , Padma Gopalan , Chirag Gupta , Shubhra S. Pasayat , Luke Mawst","doi":"10.1016/j.jcrysgro.2025.128180","DOIUrl":"10.1016/j.jcrysgro.2025.128180","url":null,"abstract":"<div><div>In this study, we developed ultra-high density InGaN/GaN nanopyramid quantum dots (QD) via Selective Area Growth (SAG) using Metal–Organic Chemical Vapor Deposition (MOCVD). We achieved QDs as small as 23 nm-diameter QDs with a density of 7–10 × 10<sup>10</sup> cm<sup>−2</sup>. The optical and structural properties of these nanostructures were analyzed using Photoluminescence (PL), Scanning Electron Microscope (SEM), X-Ray Diffraction (XRD), and Transmission Electron Microscopy (TEM). Various growth conditions and structure designs including growth temperature, growth rate, TMIn flow rate, and InGaN thickness, were studied to extend the QD emission across the full visible emission range. Power-dependent and temperature-dependent PL measurements were conducted to further investigate the optical properties. An additional longer wavelength QD spectral emission peak was suppressed at low temperatures or higher excitation power, indicating the presence of Shockley-Read-Hall recombination at low injection carrier densities.</div></div>","PeriodicalId":353,"journal":{"name":"Journal of Crystal Growth","volume":"663 ","pages":"Article 128180"},"PeriodicalIF":1.7,"publicationDate":"2025-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143847857","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-04-10DOI: 10.1016/j.jcrysgro.2025.128184
Anchen Tang , Xuefeng Han , Shuai Yuan , Yu Gao , Jianwei Cao , Xiangyang Ma , Deren Yang
To ensure the growth of high-quality semiconductor-grade Czochralski (Cz) silicon, it is crucial to control the oxygen concentration within a specified range tailored to different device applications. This study presents a two-dimensional, axisymmetric global model for heat and mass transfer during the growth of 300 mm semiconductor-grade Cz silicon crystals, based on the quasi-steady-state assumption. Intuitive distributions of oxygen concentration in both the melt and the crystal are illustrated at various solidification fractions. Simulation results are compared with our experimental results and those reported in literatures. Additionally, distribution in the crystal is presented according to Voronkov’s theory. Furthermore, the effects of turbulence models on the oxygen distribution and distribution are investigated. The results reveal that the k-ω turbulence model predicts a lower oxygen concentration compared to the k-ε model, and there is no significant difference in the distributions.
{"title":"Numerical investigation of oxygen concentration and v/G distribution in 300 mm Czochralski silicon","authors":"Anchen Tang , Xuefeng Han , Shuai Yuan , Yu Gao , Jianwei Cao , Xiangyang Ma , Deren Yang","doi":"10.1016/j.jcrysgro.2025.128184","DOIUrl":"10.1016/j.jcrysgro.2025.128184","url":null,"abstract":"<div><div>To ensure the growth of high-quality semiconductor-grade Czochralski (Cz) silicon, it is crucial to control the oxygen concentration within a specified range tailored to different device applications. This study presents a two-dimensional, axisymmetric global model for heat and mass transfer during the growth of 300 mm semiconductor-grade Cz silicon crystals, based on the quasi-steady-state assumption. Intuitive distributions of oxygen concentration in both the melt and the crystal are illustrated at various solidification fractions. Simulation results are compared with our experimental results and those reported in literatures. Additionally, <span><math><mrow><mi>v</mi><mo>/</mo><mi>G</mi></mrow></math></span> distribution in the crystal is presented according to Voronkov’s theory. Furthermore, the effects of turbulence models on the oxygen distribution and <span><math><mrow><mi>v</mi><mo>/</mo><mi>G</mi></mrow></math></span> distribution are investigated. The results reveal that the <em>k</em>-ω turbulence model predicts a lower oxygen concentration compared to the <em>k</em>-ε model, and there is no significant difference in the <span><math><mrow><mi>v</mi><mo>/</mo><mi>G</mi></mrow></math></span> distributions.</div></div>","PeriodicalId":353,"journal":{"name":"Journal of Crystal Growth","volume":"663 ","pages":"Article 128184"},"PeriodicalIF":1.7,"publicationDate":"2025-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143829942","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-04-09DOI: 10.1016/j.jcrysgro.2025.128185
Xia Tang, Milena Petković, Gagan-Kumar Chappa, Lucas Vieira, Natasha Dropka
This study evaluates four machine learning (ML) “white-box” methods − Decision Trees, Linear Regression, Python Symbolic Regression (PySR), and Sure Independence Screening and Sparsity Operation (SISSO) − and five “gray-box” methods − Gradient Boosting, XGBoost, Support Vector Machines (SVM), Gaussian Processes, and Random Forests − for analyzing data from the Cz-sapphire crystal growth process. The objective is to develop a model that achieves a balance between high predictive accuracy and interpretability in this small-data domain.
Twelve input variables − including process parameters, sapphire optical properties, and furnace geometry parameters − were analyzed in relation to five output variables: heating power, interface deflection, temperature gradients averaged at the solid/liquid interface and symmetry axis, and v/G. Using 500 data tuples from CFD simulations, the results highlighted significant performance differences across the models. SVM demonstrated superior performance in predicting temperature gradients, XGBoost excelled in interface deflection predictions, and Gradient Boosting was most effective for v/G. SISSO, known for its high interpretability, performed best in predicting heating power, particularly in cases where nonlinear noise was less pronounced.
The best performing models for each output generated explicit equations that relate inputs to outputs, feature importance plots, and 3D plots illustrating relationships within the 17-dimensional space. These findings offer theoretical insights for optimizing the Cz-sapphire crystal growth process and design.
{"title":"Comparative analysis of machine learning approaches for predicting and interpreting Cz-sapphire growth","authors":"Xia Tang, Milena Petković, Gagan-Kumar Chappa, Lucas Vieira, Natasha Dropka","doi":"10.1016/j.jcrysgro.2025.128185","DOIUrl":"10.1016/j.jcrysgro.2025.128185","url":null,"abstract":"<div><div>This study evaluates four machine learning (ML) “white-box” methods − Decision Trees, Linear Regression, Python Symbolic Regression (PySR), and Sure Independence Screening and Sparsity Operation (SISSO) − and five “gray-box” methods − Gradient Boosting, XGBoost, Support Vector Machines (SVM), Gaussian Processes, and Random Forests − for analyzing data from the Cz-sapphire crystal growth process. The objective is to develop a model that achieves a balance between high predictive accuracy and interpretability in this small-data domain.</div><div>Twelve input variables − including process parameters, sapphire optical properties, and furnace geometry parameters − were analyzed in relation to five output variables: heating power, interface deflection, temperature gradients averaged at the solid/liquid interface and symmetry axis, and v/G. Using 500 data tuples from CFD simulations, the results highlighted significant performance differences across the models. SVM demonstrated superior performance in predicting temperature gradients, XGBoost excelled in interface deflection predictions, and Gradient Boosting was most effective for v/G. SISSO, known for its high interpretability, performed best in predicting heating power, particularly in cases where nonlinear noise was less pronounced.</div><div>The best performing models for each output generated explicit equations that relate inputs to outputs, feature importance plots, and 3D plots illustrating relationships within the 17-dimensional space. These findings offer theoretical insights for optimizing the Cz-sapphire crystal growth process and design.</div></div>","PeriodicalId":353,"journal":{"name":"Journal of Crystal Growth","volume":"664 ","pages":"Article 128185"},"PeriodicalIF":1.7,"publicationDate":"2025-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143859482","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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