Study on the transport of phosphorus dopant during the n-type monocrystalline silicon growth by Czochralski technique

Effect of crucible/crystal rotation on the transport of phosphorus dopant during N-type monocrystalline silicon growth via Czochralski technique

Growth and enhanced optical properties of high-quality Eu:CaWO4 single crystal grown by Czochralski method

Monocrystalline silicon ingots are grown in a Czochralski (Cz) furnace by melting high purity silicon feedstock in a fused quartz crucible. As the standard solar cell size is getting larger, silicon ingots manufacturers have increased their demands on crucibles size and properties. Among other factors, the formation of bubbles and their growth affect the crucible`s properties and performance, which in turn are affected by the process parameters. The mechanisms of these bubbles formation and growth are still not well understood. In this study, we investigate the bubble formation and growth in three different types of crucibles before and after use in a Cz process. The crucibles have different sand qualities, -size and -chemistries. The content of hydroxyl (OH) is measured by Fourier Transform Infrared Spectroscopy (FTIR), while bubble size and distribution are measured by X-ray tomography and optical microscopy, respectively. The results indicate that a reduction in OH content correlates with increasing bubble growth. The reference crucible, which has coarse particle size distribution and standard chemistry, has the largest variation in bubble content and the largest average bubble growth for the samples investigated. The crucible with the finest particle size distribution and high purity seems to be the best choice for silicon ingot production as it experiences, on average, the lowest bubble growth in the bubble free (BF) layer. The results also show that the crucible quality (e.g. the manufacturing process and chemistry) affect the bubble content as well as the OH level.

Abstract PbMo 0.5 W 0.5 O 4 single crystals were successfully grown via the conventional Czochralski method, and their structural and optical properties were comprehensively investigated. x-ray diffraction analysis confirmed the phase purity and tetragonal scheelite-type structure with lattice parameters determined to be a = 5.3209 Å and c = 12.8099 Å. UV–Visible absorbance and transmission spectroscopy revealed a sharp absorption edge, indicative of a direct allowed electronic transition. The band gap energy was determined to be around 3.15 eV using Tauc plot analysis, supported by relatively low Urbach energy, suggesting minimal structural disorder. Photoluminescence measurements showed prominent green emission peaks at 488 and 512 nm, attributed to intrinsic structural defects and radiative recombination processes. The high optical quality and tunable band gap of PbMo 0.5 W 0.5 O 4 make it a promising candidate for ultraviolet optoelectronic devices and photocatalytic applications.

In this study, Zr:Ho:LiNbO3 crystals ([Li]/[Nb] = 0.946) were grown in air along the C-axis by Czochralski method. The occupation of Zr4+ in the crystal and the effect of Zr4+ on the internal structure of the crystal were studied by infrared absorption spectroscopy. The effect of Zr4+ on the light scattering resistance of crystal was studied by the light scattering energy threshold effect, and the mechanism of improving the light scattering resistance of crystal was discussed. The spectral properties of Ho3+ in Zr:Ho:LiNbO3 crystals are discussed based on Judd–Ofelt theory, and the laser properties of Zr:Ho:LiNbO3 crystals are evaluated.

The Czochralski method is the dominant technique for producing power-electronics-grade silicon crystals. At the beginning of the seeding stage, an excessively high (or low) temperature at the solid–liquid interface can cause the time required for the seed to reach the specified length to be too long (or too short). However, the time taken for the seed to reach a specified length is strictly controlled in semiconductor crystal growth to ensure that the initial temperature is appropriate. An inappropriate initial temperature can adversely affect crystal quality and production yield. Accurately evaluating whether the current temperature is appropriate for seeding is therefore essential. However, the temperature at the solid–liquid interface cannot be directly measured, and the current manual evaluation method mainly relies on a visual inspection of the meniscus. Previous methods for detecting this temperature classified image features, lacking a quantitative assessment of the temperature. To address this challenge, this study proposed using the duration of the seeding stage as the target variable for evaluating the temperature and developed an improved multimodal fusion regression network. Temperature signals collected from a central pyrometer and an auxiliary pyrometer were transformed into time–frequency representations via wavelet transform. Features extracted from the time–frequency diagrams, together with meniscus features, were fused through a two-level mechanism with multimodal feature fusion (MFF) and channel attention (CA), followed by masking using spatial attention (SA). The fused features were then input into a random vector functional link network (RVFLN) to predict the seeding duration, thereby establishing an indirect relationship between multi-sensor data and the seeding temperature achieving a quantification of the temperature that could not be directly measured. Transfer comparison experiments conducted on our dataset verified the effectiveness of the feature extraction strategy and demonstrated the superior detection performance of the proposed model.

The Ce3+ - doped optical quality Li2-2xZn2+x(MoO4)3 single crystals were grown by low-thermal-gradient Czochralski technique. Temperature dependences of PL (photoluminescence) and PLE (photoluminescence excitation) spectra, as well as decay curves are investigated and discussed in 77-300K range in present article. The study confirmed that ultraviolet (UV) excitation is possible and calculated the CIE chromaticity coordinates, correlated color temperature (CCT), and color rendering index for the crystals.

Precise control over defect structures is essential for tuning the functional properties of lithium niobate (LiNbO3) crystals. Although the threshold effect of Hf4+ doping is well recognized, its underlying atomic-scale mechanism, especially in systems co-doped with luminescent rare earth ions, remains unclear. In this study, we combine experimental and theoretical approaches to elucidate the Hf4+ concentration-driven threshold behavior in Dy: LiNbO3 crystals. A series of crystals with Hf4+ concentrations of 2, 4, 6, and 8 mol% were grown using the Czochralski method. Characterization through XRD and IR spectroscopy identified a threshold near 4 mol%, evidenced by an inflection in lattice constants and a pronounced blue shift of the OH− absorption peak. UV–Vis–NIR absorption spectra revealed a systematic enhancement of Dy3+f–f transition intensities, linking the global defect structure to the local crystal field of the optical activator. First-principles calculations showed that Hf4+ ions preferentially occupy Li sites, repairing antisite Nb defects (NbLi4+) below the threshold, and incorporate into Nb sites beyond it, inducing structural reorganization. Electron Localization Function analysis visualized strengthened Hf-O covalent bonding in the post-threshold regime. This work establishes a complete atomic-scale picture connecting dopant site preference, chemical bonding, and macroscopic properties, providing a foundational framework for the rational design of advanced LiNbO3-based materials.

In the semiconductor industry, the requirement for optical systems of high resolution with minimal aberration is becoming more stringent as the wavelength employed in the lithography tool is shortened. Index homogeneity, which is a key property for realizing aberration-free optics, has been conventionally characterized using a Fizeau interferometer with a visible light source. However, this method may not be technically feasible for the assessment of optical materials intended to operate in the ultraviolet (UV) wavelength region due to the steeper dispersion slope in that region. Here, we performed an optical testing for the index homogeneity of a single-crystal CaF2 optical window, which was grown via Czochralski method, by conducting interferometric measurements in the DUV wavelength region. A home-built DUV Fizeau interferometer was developed and self-calibrated to examine the CaF2 optical window for at-wavelength measurements. Furthermore, sub-aperture stitching interferometry was implemented to investigate the full aperture index distribution of the CaF2 optical window. The results were compared with the inhomogeneity measured by a commercial visible-wavelength Fizeau interferometer, which showed a value almost twice as high as that of the visible interferometer.

The Influence of γ-Irradiation on the Electrophysical Parameters of Nickel-Doped Silicon Grown by the Czochralski Method

Role of Shield Around Crystal in Czochralski Process

In this work, we conducted a 3D numerical simulation to investigate the shape of the melt-solid interface during the crystal growth of silicon using the Czochralski technique, which is widely employed in photovoltaic applications. Among the key parameters that influence the quality of the grown monocrystalline is the shape of the crystallization interface. This interface has a main role in determining the structural instability of the silicon ingot during the CZ pulling process. The primary aim of this study is to find the optimal rotation speed that results in a flat shape of the interface, which is conducive to forming a well-ordered atomic structure and thus ensuring superior crystal quality for photovoltaic use. Our findings indicate that, for a crucible with a diameter of 100 mm, an optimal rotation speed of 20 rpm gives a flat shape of the melt-solid interface. According to this study, we find that the Czochralski technique is the process that conserve the flow and the heat transfer of materials in the Cz crucible even for high rotation speed; Our results are in agreement with the experiment results. In our study for the Silicon, the heat transfer in the crucible is symmetrical even applying rotation crystal at high rates ( Vrot = 40 - 50 rpm ).

Abstract Aiming at the problems existing in traditional neodymium-doped yttrium aluminum garnet (Nd: YAG) laser crystals, such as concentration quenching effect, significant thermal effect, insufficient radiation resistance, and limited optical uniformity, the design of doped gradient concentration and doping design was carried out. Nd: YAG laser crystals with different gradient concentrations and Cr-doped Nd: YAG crystals were successfully prepared using the Czochralski method. Their laser output characteristics and performance under high-energy radiation were systematically studied. These research findings provide new gain medium growth technologies for high-energy radiation environments in outer space, holding significant scientific research value and engineering application prospects.

Deep learning with slow feature analysis for silicon single crystal growth state identification in Czochralski process

Abstract The influence of alkali and alkaline earth metal ion doping on the upconversion (UC) luminescence properties of Yb3+, Ho3+ co-doped NaBi(MoO4)2 (NBM) single crystals was systematically investigated. A series of Yb3+, Ho3+:NBM single crystals doped with Li+, K+, and Ca2+ ions were successfully grown using the Czochralski method. Their structural characteristics were analyzed through X-ray diffraction (XRD), transmission spectroscopy, and scanning electron microscopy (SEM), confirming a tetragonal crystal structure with space group I41/a. Under 980 nm and 450 nm laser excitation, the crystals exhibited distinct UC emission profiles, with dominant red and green emissions, respectively. Tauc plot analysis indicated that Ca2+ doping introduced donor levels within the crystal lattice, effectively narrowing the optical bandgap. Power-dependent luminescence studies revealed that both red and green UC emissions originated from two-photon excitation processes. Temperature-dependent photoluminescence measurements under both excitation wavelengths demonstrated that codoping with Li+, K+, and Ca2+ significantly enhanced the thermal stability of the luminescent properties. Furthermore, variable-temperature fluorescence lifetime analyses showed that alkali and alkaline earth metal ion doping effectively mitigated the luminescence lifetimes. Overall, the incorporation of Li+, K+, and Ca2+ ions was found to markedly improve both the UC luminescence intensity and thermal robustness of Yb3+, Ho3+:NBM single crystals, offering promising prospects for high-performance luminescent materials.

Materials based on silicon are widely used in energy, electronic devices, solar cells, optoelectronics, and the electronics industry. A current challenge is the controlled use of these materials in technologies under mechanical loads, radiation, and magnetic fields. The aim of the study is to investigate the change in the surface texture of silicon under the influence of a magnetic field and high-temperature plastic deformation using fractal analysis. The material for the study consisted of n-Si monocrystalline silicon wafers grown by the Czochralski method (Si-CZ), with controlled damage applied to the surface using a diamond indenter. The study employed a method to investigate dislocation movement in silicon single crystals under high-temperature plastic deformation. The experimental technique combines several materials science methods: deformation by the four-point bending test, annealing, chemical etching, and microscopy. In addition to high-temperature plastic deformation, silicon was treated in a magnetic field. The sample was placed between the poles of an electromagnet to create a magnetic field. The magnetic induction vector was perpendicular to the induced scratch. The analysis and description technique combines visual observation of photographs and fractal analysis of microimages of the chemically etched surface of silicon. Within the framework of fractal analysis, fractal dimension and lacunarity indicators were determined, which describe the unevenness and complexity of the dislocation structure of the surface. The obtained images revealed numerous dislocation exits on the surface located around the artificially created scratch, as well as changes in the surface texture. Magnetic treatment leads to the segregation of silicon atoms and impurities at the surface and the formation of a granular structure on the wafer surface. In this case, the fractality of the surface of the samples increases, while lacunarity decreases. It has been shown that under the influence of a weak magnetic field, the stabilization or blocking of the movement of already existing dislocations is possible. After turning off the field, the energy in the system is insufficient for these defects to activate and begin to move even after a second round of annealing and load. This behaviour allows for the use of sample treatment in a magnetic field to obtain defect-free silicon structures.

Abstract The Czochralski (Cz) method is widely employed for growing crystalline semiconductors from low‐vapor‐pressure materials. Although furnace designs vary depending on the material, shared hot‐zone components, such as crucibles, supports, heaters, insulation, and radiation shields‐indicate the potential for a universal Cz furnace model. This study focuses on Cz furnaces that utilize resistance heating. Data‐driven techniques including Decision Trees (DT), Symbolic Regression (SR), Artificial Neural Networks (ANN), and Shapley Additive exPlanations (SHAP) are applied to investigate the relationships between furnace design, process parameters, and crystal quality during bulk crystal growth across a range of materials and scales. DT and SR are employed for their interpretability, ANN for its predictive accuracy, and SHAP to enhance model transparency by quantifying feature importance. The analysis explores the correlation between solid–liquid interface deflection, the Voronkov criterion, and 21 input parameters describing furnace geometry, gas composition, crystal and radiation shield thermophysical properties, and growth conditions. The training dataset consists of 632 computational fluid dynamics (CFD) simulations of Cz growth involving silicon, germanium, gallium antimonide, and indium antimonide. Feature engineering using DTs is performed to reduce input dimensionality. The results demonstrate the feasibility of generating a universal Cz growth model that utilizes machine learning techniques to optimize performance across diverse grown materials, furnace configurations, and production scales.

Influence of impurities and OH-group content on viscosity, cristobalite formation and bubble evolution in fused quartz crucibles at temperatures for Czochralski process

This work presents the lasing performance of the Tm:GAGG crystal, which was successfully grown using the Czochralski method. The lasing performance of the Tm:GAGG crystal was demonstrated in both continuous-wave (CW) and Q-switching regimes. In the CW regime, the Tm:GAGG laser achieved a maximum average output power of 624 mW at 2000 nm and 220 mW at 2300 nm. Additionally, the Q-switching operation of the Tm:GAGG laser in the 2000 nm wavelength region was investigated, yielding stable pulses with a maximum output power of approximately 140 mW, a pulse duration of 190 ns, and a repetition rate of 31 kHz. To the best of our knowledge, this work represents the first detailed investigation of the lasing performance of the Tm:GAGG crystal, highlighting its potential applications in the mid-infrared wavelength region.