Numerical analysis is an effective tool to research the industrial Czochralski （CZ） crystal growth aiming to improve crystal quality and reduce manufactur- ing costs. In this study, a set of global simulations were ...Numerical analysis is an effective tool to research the industrial Czochralski （CZ） crystal growth aiming to improve crystal quality and reduce manufactur- ing costs. In this study, a set of global simulations were carried out to investigate the effect of crystal-crucible rotation and pulling rate on melt convection and solid- liquid （SL） interface shape. Through analyses of the sim- ulation data, it is found that the interface deformation and inherent stress increase during the crystal growth process. The interface deflection increases from 7.4 to 51.3 mm with an increase in crystal size from 150 to 400 mm. In addition, the SL interface shape and flow pattern are sen- sitive to pulling rate and rotation rate. Reducing pulling rate can flat SL interface shape and add energy-consuming. Interface with low deflection can be achieved by adopting certain combination of crystal and crucible rotation rates. The effect of crystal rotation on SL interface shape is less significant at higher crucible rotation rates.展开更多
The zinc oxide seed film was coated on conductive glass (FTO) substrate by the Czochralski method,Zinc acetate and hexamethylenetetramine were used as raw materials to prepare growth solution,and then ZnO film was pre...The zinc oxide seed film was coated on conductive glass (FTO) substrate by the Czochralski method,Zinc acetate and hexamethylenetetramine were used as raw materials to prepare growth solution,and then ZnO film was prepared by a low-temperature solution method.The effects of annealing temperature on the morphology,structure,stress and optical properties of ZnO films were studied.The thin films were characterized by X-ray diffraction (XRD),scanning electron microscopy (SEM),UV-visible absorption spectra (UV-vis),photoluminescence (PL) and X-ray photoelectron spectroscopy (XPS).The results show that the films are ZnO nanorods.With the increase of annealing temperature,the diameter of the rod increases,and the nanorods tend to be oriented.The band gap of the sample obtained from the light absorption spectra first increases and then decreases with the increase of annealing temperature.When the annealing temperature is 350 ℃,the crystallinity of zinc oxide film is the highest,the band gap is close to the theoretical value of pure ZnO.展开更多
Single-crystalline silicon materials with large dimensions have been widely used as assemblies in plasma silicon etching machines.However,information about large-diameter low-cost preparation technology has not been s...Single-crystalline silicon materials with large dimensions have been widely used as assemblies in plasma silicon etching machines.However,information about large-diameter low-cost preparation technology has not been sufficiently reported.In this paper,it was focused on the preparation of 400-mm silicon（100） crystal lightly doped with boron from 28-in.hot zones.Resistivity uniformity and oxygen concentration of the silicon crystal were investigated by direct-current（DC） four-point probes method and Fourier transform infrared spectroscopy（FTIR）,respectively.The global heat transfer,melt flow and oxygen distribution were calculated by finite element method（FEM）.The results show that 28-in.hot zones can replace conventional 32 in.ones to grow 400-mm-diameter silicon single crystals.The change in crucible diameter can save energy,reduce cost and improve efficiency.The trend of oxygen distribution obtained in calculations is in good agreement with experimental values.The present model can well predict the 400-mm-diameter silicon crystal growth and is essential for the optimization of furnace design and process condition.展开更多
SiGe single crystals with different Ge concentrations were measured by Fourier transform infrared （FTIR） spectroscopy at room temperature （RT） and 10 K. A new peak appears at the wave number of 710 cm^-1 and the s...SiGe single crystals with different Ge concentrations were measured by Fourier transform infrared （FTIR） spectroscopy at room temperature （RT） and 10 K. A new peak appears at the wave number of 710 cm^-1 and the spectroscopy becomes clearer with an increase in Ge content. The absorption strength and wave sharp of the 710 cm^-1 peak are independent of temperature. The relation of the absorption coefficient amax, the band width of half maximum （BWHM） Wit2 of the 710 cm^-1 peak, and the Ge concentration is determined with the Ge content obtained by SEM-EDX. The conversion factor is k = 1.211 at 10 K. Therefore, the Ge content in high concentration Ge doped CZ-Si single crystals can be determined by FTIR.展开更多
A numerical study was carried out to describe the flow field structure of an oxide melt under 1) the effect of internal radiation through the melt (and the crystal), and 2) the impact of surface tension-driven forces ...A numerical study was carried out to describe the flow field structure of an oxide melt under 1) the effect of internal radiation through the melt (and the crystal), and 2) the impact of surface tension-driven forces during Czochralski growth process. Throughout the present Finite Volume Method calculations, the melt is a Boussinnesq fluid of Prandtl number 4.69 and the flow is assumed to be in a steady, axisymmetric state. Particular attention is paid to an undulating structure of buoyancy-driven flow that appears in optically thick oxide melts and persists over against forced convection flow caused by the externally imposed rotation of the crystal. In a such wavy pattern of the flow, particularly for a relatively higher Rayleigh number , a small secondary vortex appears nearby the crucible bottom. The structure of the vortex which has been observed experimentally is studied in some details. The present model analysis discloses that, though both of the mechanisms 1) and 2) end up in smearing out the undulating structure of the flow, the effect of thermocapillary forces on the flow pattern is distinguishably different. It is shown that for a given dynamic Bond number, the behavior of the melt is largely modified. The transition corresponds to a jump discontinuity in the magnitude of the flow stream function.展开更多
本文从固相反应温度、晶转速率、生长速率及降温速率几个方面,探索分析了采用提拉法生长大尺寸Yb∶CALGO晶体的工艺。通过对比不同温度下烧结反应后的多晶料XRD图谱发现,原料在1350℃可以充分反应,根据所生长晶体的开裂截面形貌与晶体...本文从固相反应温度、晶转速率、生长速率及降温速率几个方面,探索分析了采用提拉法生长大尺寸Yb∶CALGO晶体的工艺。通过对比不同温度下烧结反应后的多晶料XRD图谱发现,原料在1350℃可以充分反应,根据所生长晶体的开裂截面形貌与晶体表面光滑度来优化晶转速率和生长速率,通过变温拉曼光谱分析降温速率导致开裂的成因,结合不同降温速率获得了不同方向的晶面应力分布图,发现对于沿着c轴生长的Yb∶CALGO晶体来说,降温速率过快更容易导致(001)面的热应力积累,这也是导致晶体在退火过程中开裂的主要诱因。采用多种手段优化晶体生长工艺后,实现了ϕ50 mm×110 mm Yb∶CALGO晶体的稳定生长,晶体具有较低的散射损耗(0.001796 cm^(-1))和较高的光学均匀性(4.21×10^(-5)),可以实现多种尺寸和形状的晶体元件加工,为进一步研制Yb∶CALGO板条激光器和超快激光器提供技术支撑。展开更多
基金financially supported by the Major National Science and Technology Projects (No. 2009ZX02011)
文摘Numerical analysis is an effective tool to research the industrial Czochralski （CZ） crystal growth aiming to improve crystal quality and reduce manufactur- ing costs. In this study, a set of global simulations were carried out to investigate the effect of crystal-crucible rotation and pulling rate on melt convection and solid- liquid （SL） interface shape. Through analyses of the sim- ulation data, it is found that the interface deformation and inherent stress increase during the crystal growth process. The interface deflection increases from 7.4 to 51.3 mm with an increase in crystal size from 150 to 400 mm. In addition, the SL interface shape and flow pattern are sen- sitive to pulling rate and rotation rate. Reducing pulling rate can flat SL interface shape and add energy-consuming. Interface with low deflection can be achieved by adopting certain combination of crystal and crucible rotation rates. The effect of crystal rotation on SL interface shape is less significant at higher crucible rotation rates.
基金Funded by Henan International Science and Technology Cooperation Program (No.152102410035)Ph D Research Startup Foundation of Henan University of Science and Technology(No.13480107)。
文摘The zinc oxide seed film was coated on conductive glass (FTO) substrate by the Czochralski method,Zinc acetate and hexamethylenetetramine were used as raw materials to prepare growth solution,and then ZnO film was prepared by a low-temperature solution method.The effects of annealing temperature on the morphology,structure,stress and optical properties of ZnO films were studied.The thin films were characterized by X-ray diffraction (XRD),scanning electron microscopy (SEM),UV-visible absorption spectra (UV-vis),photoluminescence (PL) and X-ray photoelectron spectroscopy (XPS).The results show that the films are ZnO nanorods.With the increase of annealing temperature,the diameter of the rod increases,and the nanorods tend to be oriented.The band gap of the sample obtained from the light absorption spectra first increases and then decreases with the increase of annealing temperature.When the annealing temperature is 350 ℃,the crystallinity of zinc oxide film is the highest,the band gap is close to the theoretical value of pure ZnO.
基金financially supported by the Major National Science and Technology Projects(No.2008ZX02401)
文摘Single-crystalline silicon materials with large dimensions have been widely used as assemblies in plasma silicon etching machines.However,information about large-diameter low-cost preparation technology has not been sufficiently reported.In this paper,it was focused on the preparation of 400-mm silicon（100） crystal lightly doped with boron from 28-in.hot zones.Resistivity uniformity and oxygen concentration of the silicon crystal were investigated by direct-current（DC） four-point probes method and Fourier transform infrared spectroscopy（FTIR）,respectively.The global heat transfer,melt flow and oxygen distribution were calculated by finite element method（FEM）.The results show that 28-in.hot zones can replace conventional 32 in.ones to grow 400-mm-diameter silicon single crystals.The change in crucible diameter can save energy,reduce cost and improve efficiency.The trend of oxygen distribution obtained in calculations is in good agreement with experimental values.The present model can well predict the 400-mm-diameter silicon crystal growth and is essential for the optimization of furnace design and process condition.
基金The work is financially supported by the National Natural Science Foundation of China (No. 59772037)the NaturalScience Foundation of Hebei Province, China (No. 500016).
文摘SiGe single crystals with different Ge concentrations were measured by Fourier transform infrared （FTIR） spectroscopy at room temperature （RT） and 10 K. A new peak appears at the wave number of 710 cm^-1 and the spectroscopy becomes clearer with an increase in Ge content. The absorption strength and wave sharp of the 710 cm^-1 peak are independent of temperature. The relation of the absorption coefficient amax, the band width of half maximum （BWHM） Wit2 of the 710 cm^-1 peak, and the Ge concentration is determined with the Ge content obtained by SEM-EDX. The conversion factor is k = 1.211 at 10 K. Therefore, the Ge content in high concentration Ge doped CZ-Si single crystals can be determined by FTIR.
文摘A numerical study was carried out to describe the flow field structure of an oxide melt under 1) the effect of internal radiation through the melt (and the crystal), and 2) the impact of surface tension-driven forces during Czochralski growth process. Throughout the present Finite Volume Method calculations, the melt is a Boussinnesq fluid of Prandtl number 4.69 and the flow is assumed to be in a steady, axisymmetric state. Particular attention is paid to an undulating structure of buoyancy-driven flow that appears in optically thick oxide melts and persists over against forced convection flow caused by the externally imposed rotation of the crystal. In a such wavy pattern of the flow, particularly for a relatively higher Rayleigh number , a small secondary vortex appears nearby the crucible bottom. The structure of the vortex which has been observed experimentally is studied in some details. The present model analysis discloses that, though both of the mechanisms 1) and 2) end up in smearing out the undulating structure of the flow, the effect of thermocapillary forces on the flow pattern is distinguishably different. It is shown that for a given dynamic Bond number, the behavior of the melt is largely modified. The transition corresponds to a jump discontinuity in the magnitude of the flow stream function.
文摘本文从固相反应温度、晶转速率、生长速率及降温速率几个方面,探索分析了采用提拉法生长大尺寸Yb∶CALGO晶体的工艺。通过对比不同温度下烧结反应后的多晶料XRD图谱发现,原料在1350℃可以充分反应,根据所生长晶体的开裂截面形貌与晶体表面光滑度来优化晶转速率和生长速率,通过变温拉曼光谱分析降温速率导致开裂的成因,结合不同降温速率获得了不同方向的晶面应力分布图,发现对于沿着c轴生长的Yb∶CALGO晶体来说,降温速率过快更容易导致(001)面的热应力积累,这也是导致晶体在退火过程中开裂的主要诱因。采用多种手段优化晶体生长工艺后,实现了ϕ50 mm×110 mm Yb∶CALGO晶体的稳定生长,晶体具有较低的散射损耗(0.001796 cm^(-1))和较高的光学均匀性(4.21×10^(-5)),可以实现多种尺寸和形状的晶体元件加工,为进一步研制Yb∶CALGO板条激光器和超快激光器提供技术支撑。
